Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold Rolling Mill at Varying Surface Roughness

*Olayinka Olaogun, Esther Titilayo Akinlabi and Cynthia Samuel Abima*

## **Abstract**

AA8015-alloy is a general-purpose aluminium alloy having a wide range of applications. Electrochemical corrosion testing of cold-rolled AA8015-alloy processed by reversing cold-rolling mill at different surface roughness in natural seawater were investigated. The AA8015-alloy utilised in this study was cold-rolled in a reversible Achenbach cold-rolling mill in four number of passes to a gauge thickness of 1.2 mm. This industrial cold rolling process was achieved at Tower Aluminium Rolling Mill, Sango-Ota, Nigeria. The different surface roughness's each with three cold mounted samples, 1.54 μm, 0.83 μm, 0.18 μm and 0.04 μm were achieved on automated polishing machine using 320-grit, 800-grit, 1200-grit and diamond abrasive MD-Mol respectively. Electrochemical corrosion experiments were conducted on the samples in natural seawater using a computer-controlled potentiostat in an open polarisation cell set-up at room-temperature. The corrosion behaviour on surface morphologies of the samples was observed by high-mega-pixel camera and scanning electron microscope. Findings reveal asymmetric polarisation curves, and the polarisation resistance increases as the surface roughness decreases. Consequently, corrosion-rate reduces as the surface get smoother and EDS elemental analysis shows the existence of insoluble sulphate and chloride complexes formed on the surfaces. Conclusively, surface roughness affects the corrosion resistance of cold-rolled AA8015-alloy in natural seawater.

**Keywords:** cold-rolled AA8015-alloy, electrochemical corrosion, reversible rolling mill, surface roughness, corrosion rate analysis

## **1. Introduction**

The useful lifespan of any component or device is always established at its design and manufacturing stage [1]. In extractive metallurgy, large billets have to be reduced by mechanical deformation processes such as forging, rolling and extrusion for further reduction and change in their shapes. There are three basic temperature ranges in metal forming at which the metal (workpiece) can be formed which are hot working, warm working and cold working [2]. Cold working is a strengthening mechanism that involves plastic deformation. This strengthening mechanism is mostly utilised in ductile metals. In addition, cold working takes place when the processing temperature of the mechanical deformation of the ductile metal is below the recrystallization temperature [3–5]. Cold working in mechanical rolling process is eminent as compared to pressing, drawing, spinning and extruding.

The cold working in rolling process, known as cold rolling, involves deforming the ductile metal by using rolls at low temperatures, especially at temperatures below the recrystallization temperature of the specific metal. Cold rolling processes are achieved by using rolling mills to produce metal sheets of a certain required thickness. The vast majority of cold rolled metal is in the form of flat rolling. Worth noting is the fact that cold rolling has enormous benefits in its ability to manufacture products from relatively large pieces of metal at very high speed in a continuous manner with good surface finish, highly accurate tolerances and stronger products. In addition, cold rolling process eliminates shrinkage effect, increases hardness and elastic limit. It also promote decrease in ductility due to strain hardening effect [2, 4, 6, 7].

There has been advances in research on corrosion behaviour of cold rolled metalalloys in various solutions reported. Liu et al. [8] carried out electrochemical measuring technique on metastable Cr-Mn-Ni-N austentic stainless steel in acidic medium. Their findings shows that Fe and Cr dissolutes on the stainless steel surface in the process of corrosion which is clearly facilitated by the cold rolling deformation. Studies by Ma et al. [9] demonstrated that high strained cold rolling deformation such as 70 and 90 percent reduction in thickness in Ta-4 W alloy improves corrosion resistance due to preferential crystallographic orientations. More studies [10–13], also confirms that cold rolling deformation effect in metal-alloys greatly influence the corrosion current density and corrosion potentials.

Moreover, open literature reports evidence of aluminium and its alloys corroding under typical applications. To mention a few. Rao et al. [14] in their literature review on stress-corrosion cracking, confirm that 2xxx, 5xxx and 7xxx aluminium alloys are susceptible to stress-corrosion cracking. Moreover, a review on the corrosion inhibition performance evaluation for aluminium and its alloys in chloride and alkaline solutions by Xhanari and Finsgar [15], confirms evidence of corrosion in aluminium. Further scholarly articles [16–25] reported also indicate that aluminium and its alloys corrode, despite its formation of a natural oxide layer that is chemically inert. However, corrosion study on aluminium 8-series especially aluminium 8015-alloy is yet to be reported.

Conducting effect of corrosion on varying degree of surface roughness in cold rolled metal reduction has been a grey area of research. Therefore, this research work focus on an extensive in-depth experimental investigation on the corrosion behaviour of cold-rolled AA8015-alloy in natural seawater solution at varying surface roughness condition.

## **2. Achenbach reversing mill and cold rolling process**

The Achenbach reversing cold rolling mill utilised in this study is a 4-high single stand unit at Tower Aluminium Rolling Mill, Sango-Ota, Nigeria. The 4-high

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*

reversing mill detail description and pictorial representation are presented in **Table 1** and **Figure 1** respectively.

The annealed coiled AA8015-alloy with 7 mm sheet thickness is heated up to approximately 120°C before been loaded into the deforming rolls at industrial ambient temperature. The alloy sheet was cold rolled successively at thermal equilibrium maintained at about 70°C by passing it back and forth in four successive pass


#### **Table 1.**

*Description of Achenbach 4-high reversing cold rolling mill at towers aluminium rolling mill.*

#### **Figure 1.**

*Pictures of Achenbach 4-high reversible cold rolling mill at tower aluminium rolling mill; (a) left-end of the loaded coil, (b) cold rolling process, (c) right-end of the loaded coil, (d) computer numeric control unit, (e) bigger view of the 4-high reversible cold mill, (f) end view of the rolls.*

schedules in alternate directions until desired thickness of 1.2 mm is attained. The pass schedules were chosen to maintain reasonable constant drive power and rolling force during successive passes.

## **3. Experimental details**

### **3.1 Material, sample preparation and electrolyte solution**

The cold-rolled AA8015-alloy specimen was investigated using Bruker Elemental Optical Spectrometry and the obtained elemental composition is given in **Table 2**. The cold-rolled alloy specimen was square-cut using automated Mecatome T300 cutting machine embedded with a 10S25 cut-off wheel based on the inscribed markings on the surface having dimensions 10 mm by 10 mm. Twelve corrosion specimen samples were prepared according to ASTM standard G1–03 [26] and cold mounted using EpoFix Resin and hardener following Struers application note for cold mounting procedures [27]. Further surface treatment was done on the cold mounted samples using SiC emery paper of varying 320, 800 and 1200 grit and diamond polished with MD-Mol disc surface on automated grinding/polishing machine. Four different surface conditions were attained after cleaning with distilled water and acetone. The surface roughness (*Ra*) was determined with HOMMEL-ETAMIC TURBO roughness and contour metrology, for each surface conditions given in **Table 3**.

A natural seawater electrolyte solution was utilised in the experiment with a pH of 7.04, taken from the Sea at Durban, South Africa. **Table 4** depicts the chemical composition of the seawater at 3.5% salinity. The major ion in parts per million (ppm) is shown.

### **3.2 Electrochemical measurements**

Potentiodynamic electrochemical technique was utilised in determining the corrosion behaviour of the cold-rolled AA8015-alloy at varying surface roughness following


**Table 2.**

*Chemical composition of AA8015-alloy in weight per cent.*


**Table 3.**

*Surface roughness values of cold-rolled AA8015-alloy corrosion samples under different surface conditions.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*


#### **Table 4.**

*Major ion composition of seawater at 3.5% salinity [28].*

ASTM standard G5 [29]. The potentiodynamic polarisation curves were generated using the Ivium Compact-Stat Potentiostat computer-controlled with accustomised Ivium corrosion analysis software to produce Tafel fit lines. Electrochemical experiments were conducted for three samples of the cold-rolled alloy at each surface roughness carried out at room temperature in an open glass cell containing 200 ml solution of natural seawater. This is important to confirm reproducibility and precision. Open circuit potential (*Eoc*) measurement of each sample of the cold-rolled

**Figure 2.** *Electrochemical corrosion experimental set-up; (a) Ivium compact-stat Potentiostat, (b) an open glass cell system.*

aluminium 8015-alloy at varying surface roughness was first determined, according to ASTM standard G69 [30]. The polarisation cell set-up for determination of *Eoc* consist of connections of the working electrode (prepared cold-rolled aluminium 8015-alloy samples at different surface roughness) and the silver/silver chloride reference electrode in natural seawater electrolyte solution to the potentiostat. Subsequent potentiodynamic experiments carried out utilised a conventional three-electrode polarisation cell that includes a platinum counter-electrode. A linear potential sweep in the anodic direction was performed at a scan rate of 0.167 mV/s, starting from 250 mV below the *Eoc* and terminating at 250 mV above the *Eoc*. The scanning electron microscope images were recorded to ascertain the interaction of seawater medium with the alloy surface using TESCAN VEGA Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy (EDS). **Figure 2** shows the experimental polarisation cell set-up accordingly.

## **4. Results and discussion**

## **4.1 Open circuit potential (Eoc) and potentiodynamic polarisation result**

The measured potential of the working electrode (cold-rolled AA8015-alloy) at varying surface roughness is given in **Figure 3**, as a function of time for an hour duration. The variations of the open circuit potential against Ag/AgCl with the time plot for the three samples show a steady state variation almost throughout the time duration with relatively stable drifting within 0.1 V for samples with surface roughness 1.54 μm and 0.83 μm, and 0.05 V for samples with surface roughness 0.18 μm and 0.04 μm respectively. The open circuit potential (*Eoc*) values for the three samples at each surface roughness all show electronegative potentials, given in **Table 5**. These steady-state *Eoc* values were taken at the last 3600 seconds. The anodic and cathodic reactions on the alloy surface are in equilibrium at these potentials.

#### **Figure 3.**

*Variation of open circuit potential with time for cold-rolled aluminium 8015-alloy at (a) 1.54 μm; (b) 0.83 μm; (c) 0.18 μm and; (d) 0.04 μm surface roughness's in natural seawater.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*


**Table 5.**

*Open circuit potentials (*Eoc*) for cold rolled AA8015 with varying surface roughness.*

**Figure 4.** *Polarisation curves of cold-rolled AA8015-alloy immersed in natural sea water at surface roughness's (a) Ra ≈ 1.54 μm; (b) Ra ≈ 0.83 μm; (c) Ra ≈ 0.18 μm; (d) Ra ≈ 0.04 μm.*

Likewise, **Figure 4** shows the polarisation curves generated for each potentiodynamic polarisation test for all the samples. Observations for each curve shows similarity in shape and are asymmetric. Furthermore, the Tafel behaviour on the cathodic side extends over a wider potential range than on the anodic side. In addition, the anodic current rose more steeply with changes in potential than the cathodic current. This indicates that reduction reaction occurs at slower rate than oxidation reaction. Therefore, cathodic reaction controls the electrochemical corrosion of the cold-rolled AA8015-alloy. The drifting occurrence in the polarisation curves confirms electrochemical noise. These suggest indication of sudden inert oxide-layer film rupture causing dissolution of the AA8015-alloy.

## **4.2 Corrosion rate analysis**

The Tafel plot analysis on the cold-rolled AA8015-alloy samples at each surface roughness condition are presented in **Figures 5**–**8**. The current-potential data obtained

**Figure 6.**

*Tafel analysis of cold-rolled aluminium 8015-alloy at* Ra *≈ 0.83 μm. (a) Sample 1; (b) sample 2; (c) sample 3.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*

**Figure 7.** *Tafel analysis of cold-rolled aluminium 8015-alloy at* Ra *≈ 0.18 μm. (a) Sample 1; (b) sample 2; (c) sample 3.*

**Figure 8.**

*Tafel analysis of cold-rolled aluminium 8015-alloy at* Ra *≈ 0.04 μm. (a) Sample 1; (b) sample 2; (c) sample 3.*

were plotted as logarithms of current against potential for both the anodic and cathodic branches. Straight lines that best fit the data at high potentials were achieved at selected potential range markers on both anodic and cathodic curves. The point of intersection yields the corrosion current density (*Icorr*) and the corrosion potential (*Ecorr*). The corresponding electrochemical kinetic parameters and corrosion rate for each surface roughness condition of the cold-rolled AA8015-alloy in natural seawater solution were computed and given in **Tables 6**–**9**.


### **Table 6.**

*Corrosion rate analysis of cold-rolled AA8015-alloy at* Ra *≈ 1.54 μm.*


### **Table 7.**

*Corrosion rate analysis of cold-rolled AA8015-alloy at* Ra *≈ 0.83 μm.*


#### **Table 8.**

*Corrosion rate analysis of cold-rolled AA8015-alloy at* Ra *≈ 0.18 μm.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*


#### **Table 9.**

*Corrosion rate analysis of cold-rolled AA8015-alloy at* Ra *≈ 0.04 μm.*


#### **Table 10.**

*Mean values of polarisation resistance and corrosion rate of cold-rolled AA8015-alloy at different surface roughness values.*

The mean value calculated results in **Table 10**, reveals the effect of polarisation resistance (*Rp*) and corrosion rate on the surface roughness of cold-rolled AA8015 alloy in natural seawater solution at room temperature. Significant observation reveals increase in *Rp* values as the cold-rolled alloy surface roughness get smoother. Low *Rp* value of 9.088 kΩ recorded for surface roughness, *Ra* ≈ 1.54 μm shows low resistance to corrosion attack as compared to high *Rp* value of 30.84 kΩ recorded for surface roughness, *Ra* ≈ 0.04 μm. This is evidence in the visual inspection macrograph after electrochemical corrosion. See **Figure 9**. Similarly, the rate of corrosion decreases as the surface roughness reduces.

### **4.3 Visual inspection and SEM analysis**

The macrographs in **Figure 9** were taken after electrochemical corrosion experiment. The presence of black spots on the surface reveals the extent of the attack in the form of localised corrosion. The magnitude of dissolution of the cold-rolled aluminium alloy in natural seawater solution revealed in the macrographs confirms increase in corrosion resistance as the surface roughness becomes smoother.

Further microstructural analysis using Scanning Electron Microscope (SEM) revealed corrosion by pitting in all the surface roughness conditions, given in **Figures 10**–**13**. In addition, substantial insoluble substrate complexes were observed, confirming evidence of corrosion. However, SEM images at surface roughness, *Ra* ≈ 1.54 μm is without the presence of insoluble substrate complex. This could be due to the high mechanical surface flaws because of the 320-grit SiC paper. Moreover, EDS

**Figure 9.**

*Macrographs showing localised corrosion attack on cold-rolled AA8015-alloy surface samples after electrochemical corrosion. (a)* Ra *≈ 1.54 μm; (b)* Ra *≈ 0.83 μm; (c)* Ra *≈ 0.18 μm (d)* Ra *≈ 0.04 μm.*

analysis in **Figure 14** shows sulphur and chlorine ions present in the insoluble substrate confirming the adsorption chloride and sulphur molecules in seawater at the defective spots were oxide layer is dissolved.

## **5. Conclusions and future work**

Electrochemical corrosion of the cold-rolled AA8015-alloy at varying surface roughness in natural seawater was investigated. This was shown in the open circuit potential and potentiodynamic polarisation. Outcome revealed:


For in-depth analysis and to understand the active corrosion characteristics of cold rolled AA8015-alloy and in addition to the relationship between the microstructural

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*

#### **Figure 10.**

*SEM images of corroded cold-rolled AA8015 sample at* Ra *≈ 1.54 μm. (a) Image before corrosion at 314-x magnification; (b-d) images after corrosion at increased magnifications.*

evolution and corrosion behaviour of cold rolled AA8015 in natural sea water. Future investigation using X-ray diffraction (XRD), electron back scatter diffraction (EBSD) and X-ray photoelectron spectroscopy (XPS) are recommended.

**Figure 11.**

*SEM images of corroded cold-rolled AA8015 sample at* Ra *≈ 0.83 μm. (a) Image before corrosion at 209-x magnification; (b-d) images after corrosion at increased magnifications.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*

**Figure 12.**

*SEM images of corroded cold-rolled AA8015 sample at* Ra *≈ 0.18 μm. (a) Image before corrosion at 219-x magnification; (b-d) images after corrosion at increased magnifications.*

**Figure 13.**

*SEM images of corroded cold-rolled AA8015 sample at* Ra *≈ 0.04 μm. (a) Image before corrosion at 246-x magnification; (b-d) images after corrosion at increased magnifications.*

*Electrochemical Corrosion Study of Cold-Rolled AA8015-Alloy Processed by Reversing Cold… DOI: http://dx.doi.org/10.5772/intechopen.110060*

## **Additional information**

This paper is a revised and expanded version of a paper entitled [Corrosion behaviour of cold-rolled aluminium 8015-alloy in natural sea water at 0.18 μm surface roughness] accepted for presentation at [4th International Conference on Mechanical, Manufacturing and Plant Engineering, Melaka, Malaysia. November 14–15, 2018].

## **Author details**

Olayinka Olaogun<sup>1</sup> \*, Esther Titilayo Akinlabi<sup>2</sup> and Cynthia Samuel Abima<sup>3</sup>

1 Department of Mechanical Engineering, Kwara State University, Nigeria

2 Department of Mechanical and Construction Engineering, Northumbria University, Newcastle, United Kingdom

3 Department of Mechainical Engineering Science, University of Johannesburg, South Africa

\*Address all correspondence to: yinka.olaoluwa@live.com

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[11] Pengfei D, Deng S, Li X. Mikania micrantha extract as a novel inhibitor for the corrosion of cold rolled steel in Cl2HCCOOH solution. Journal of Materials Research and Technology. 2022;**19**:2526-2545, ISSN 2238-7854,. DOI: 10.1016/j.jmrt.2022.06.026

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[13] Asaolu AO, Omotoyinbo JA, Oke SR, Falodun OE, Olubambi PA. Effect of nickel addition on microstructure, tensile and corrosion properties of cold rolled silicon bronze. Materials Today: Proceedings. 2021;**38**(Part 2):1147-1151, ISSN 2214-7853. DOI: 10.1016/j.matpr.2020.07.136

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## **Chapter 11**

## Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process

*Bazani Shaik, M. Muralidhara Rao, G. Harinath Gowd, B. Durga Prasad and J. Ranga*

## **Abstract**

Friction stir processing is a very promising method widely joining varieties of metals in other relatively marine, shipbuilding, automotive industries, aeronautical, and heavy machinery industries due to the following advantages, such as, low porosity, less tendency to cracking, and fewer defects. Research investigates the mechanical properties for input parameters such as welding speed, rotational speed, tilt angle, and axial force, and output parameters such as tensile strength, microhardness on advancements of aluminum alloys by using friction stir processing based on cost. Taguchi L9 used for the carrying research on experiments with trailing on parent materials in different ranges of input responses on welding speed is 60 mm/min, rotational speed 1250 rpm, tilt angle 3°, and axial force of 12 KN output responses tensile strength are 167 MPa measured on the basis of ASTM on specimens and analysis for carrying and using design of experiments and mathematical modeling, the relations with empirical process useful for the development for automated design.

**Keywords:** aeronautical industries, mechanical properties, advancements of aluminum alloys, friction stir process, welding

## **1. Introduction**

The friction stir welding process is currently very useful for ship manufacturing and industry-oriented aircraft and automotive for butt, lap with spot-on dissimilar joining of applicability Al-alloys and other materials of Mg-alloys, the production of mass of light transportation systems and fuel consumption has significantly reduced [1]. Studied resistance of ironing with process aluminum alloys are increased to improve the silicon oxide nanoparticles for the limit of iron [2]. Studied mechanical properties and microstructural evaluation of AZ31B of sheets has 3 mm thickness welded of optimum conditions. The material of workpieces for joining friction stir processing with tool is shown in **Figure 1** [3, 4]. Studies on tempered steel with quench property are feasible of tensile strength 1635 Mpa and research focus of different types of high carbon steels and medium are accepted successfully of friction stir welds. Joining of Al6061 or NiTip composite with the distribution of homogeneous

particles without product interface reaction is prepared successfully by friction stir processing took place combination of good damping with thermal physical properties on the treatment of heat process in the composite [ 5 , 6 ]. Al–Li 2099 T86 of stress corrosion cracking applications and [ 7 , 8 ] developments of new alloy in aircraft industries are identified aluminum–lithium alloys with the [ 9 , 10 ] substitute of high strength aluminum alloys on spacecraft manufacturing and launchers. The properties of strength, toughness, and [ 11 , 12 ] stiffness are adopted with aluminum alloys. The aluminum–lithium alloys advanced took place with stress corrosion [ 13 , 14 ] cracking on structural space applications. The parameters used for welding have [ 15 , 16 ] cohesive bands and circular shapes and path studied of tool intention.

## **2. Materials and methods**

 The friction stir process mainly involves the basic need for materials and methods influences by welding of dissimilar AA7075T651 and AA6082T651 with having thickness of 6 mm and by using advanced numerically controlled stir process are carried out experiments on the basis of lot of literature survey and trail error methods on input parameters varying with proportionate condition done at Annamalai university. Chemical compositions with base material are shown in **Table 1** . The specimens of the plate taken dimensions on the basis of gap is 100 mm × 50 mm × 6 mm. The dimensions cut by the edges with smooth areas to do easily joining process of butt welding for the two dissimilar aluminum alloys are placed advancing side and retreating side are shown in **Figure 2** for the fixed clamps will be adjusted for specimens.


 **Table 1.**

 *The chemical compositions of AA7075T651 and AA6082T651.* 

*Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*

**Figure 2.** *Weld position of dissimilar aluminum alloys of friction stir welding.*

The designed tool with advanced condition material taken as M2-Grade SHSS tool diameter of the shoulder is 18 mm and length of the probe is 6 mm. After the friction stir processing, the weld zone appears perfectly, for the testing of the welding specimens are taken as standards of ASTM E8 and tensile test specimens before shown in **Figure 3** and specimens after testing are shown in **Figure 4**. The combination and particular diameter of standard specimens are taken for the impact strength shown in **Figure 5**. The AA7075T651 advancing side and AA6082T651 in retreating side to have the proper joining of materials and for the improvement of mechanical properties.

**Figure 3.** *Specimens of tensile test before testing with ASTM E8.*

#### **Figure 4.**  *Specimens of tensile test after testing.*

### **Figure 5.**

 *Specimens of impact test.* 


#### **Table 2.**

 *Input variables for actual and coded.* 

The advanced methodology applied for different parameters to obtain easy way of influencing the properties of mechanical by using dissimilar welding of notations and units are described in **Table 2** and experimental design of Taguchi model input parameters and output parameters is shown in **Table 3** .

*Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*


#### **Table 3.**

*Experimental design of Taguchi model.*

## **3. Design of expert**

The design of experts in series with the test for the researcher useful for changes in input variables on a processor system is shown in **Figure 6** due to the effect of variables of responses measured. The applicability of computer simulation models and physical on the factorial designs took place sensitively for the estimation of the combination of effect for two or more factors.

The design of experiments and methods of the traditional difference taken place approach in a better way of values on variables of parallel and it does not cover the main effects on the variables on the different interactions and the possibility of approach for identifying optimal values on the variables of combination with

**Figure 6.** *Process model of the design of expert.*

**Figure 7.** *Influence of rotational speed on tensile strength.*

experimental runs. The design of experiments is carried out in four phases: Screening, Planning, Optimization, and Verification.

The influence of rotational speed on tensile strength has increased based on the tool welding speed varies the strength with respect to the elongation has improved to the maximum extent depends on the rotational speed. **Figure 7** shows the increases in rotational speed depends on the heat increases at the welding zone area. The friction coefficient decreases with the melting condition. The friction stir process region intricate the fine particles will be distributed in the uniform portion. The effect of tool stirred the position on the flow of metal optimum depends on the increase of tensile strength.

The percentage of elongation along transverse direction obtained from the tensile test plotted against the welding speed. The plates (**Figure 8**) shows welded with a rotational speed of 1250 rpm and weld speed of 40 mm/min. While the plates were welded at 1150 rpm and 60 mm/min. The influence shows the properties of higher heat input on the basis of influenced elongation.

The influence of tilt angle on tensile strength (**Figure 9**) shows the manner of the position at the bottom area of the welded part and it will increase the position of tool speed with respect to the material and designed shoulder based. The region of the position will make difference between the tool changes the yield strength to improve the microstructure with ductility.

The influence of axial force on tensile strength (**Figure 10**) shows the significance of friction stir processing at the joining area. The joint took place in the position

*Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*

**Figure 8.** *Influence of welding speed on tensile strength.*

**Figure 9.** *Influence of tilt angle on tensile strength.*

**Figure 10.** *Influence of axial force on tensile strength.*

of rotational speed is 1250 rpm and tensile strength 164.99 MPa and the welding speed takes the major role due to increasing of force is 12 KN has the strength will be superior at the position of part counter.

The influence of rotational speed on impact strength produces **Figure 11** shows the frictional heat required to plasticize the material and also the effect of proper mixing of the dissimilar alloys. The changes in the position of the part speed will be low and have good mechanical properties at the welding speed is higher.

The influence of welding speed on impact strength shows **Figure 12** maintains the region with the center point of the notch makes the higher energy in order to analyze the impact energy at an instant with the increasing of welding speed 60 mm/min and impact energy of the notch shows 9.2 J.

The influence of tilt angle on impact strength shows **Figure 13** increases of the impact energy with 11 J with respect to the tilt angle 3° will be maximum of increasing tool tilt angle.

The influence with axial force on impact strength **Figure 14** shows the tool stirring action plays a major role of the part to increase the rotational speed with the resultant of the weld area. The surfaces that occur groove condition because insufficient material will be visible. The zone of the weld part decreases with rotational speed due to the effect of distribution with temperature at the area of weld zone.

The influence of rotational speed on elongation shows in **Figure 15** with the increase of rotational speed on the higher input of heat. The position of the tool will be the friction decreases with the heat input condition. The friction stir processing is *Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*

**Figure 11.** *Influence of rotational speed on impact strength.*

**Figure 12.** *Influence of welding speed on impact strength.*

**Figure 13.** *Influence of tilt angle on impact strength.*

**Figure 14.** *Influence of axial force on impact strength.*

*Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*

**Figure 15.** *Influence of rotational speed on elongation.*

#### **Figure 16.**

*Influence with welding speed on elongation.*

the best condition for the optimized region on the fine particles with the distribution of uniform.

The percentage of elongation along transverse direction obtained from the tensile test plotted against the welding speed. **Figure 16** shows plates welded with rotational speed is 1250 rpm and weld speed of 40 mm/min. While plates welded rotational

speed is 1150 rpm and welding speed 60 mm/min. The proportion area influences the heat input due to the elongation of 11.25%.

The influence of tilt angle on elongation shown in **Figure 17** is the position of tool depends on the material adjustment at the shoulder region of the part condition varies with the improvement condition in a friendly environment at the joining portion of

**Figure 17.** *Influence of tilt angle on elongation.*

**Figure 18.** *Influence of axial force on elongation.*

*Experimental Investigations on Advancements of Aluminum Alloys with Friction Stir Process DOI: http://dx.doi.org/10.5772/intechopen.108885*

the yield works due to the microstructure will give perfect condition in the region of the part due to tilt angle maximum 3° and elongation of 9.7%.

The influence of axial force on elongation shows in **Figure 18** with the flow of zone part due to higher heat input it occurs at the probe area. The tool pin changes the position in order to move the actual flow of material to control the plastic deformation easily. The shoulder will be the major portion force will increase the depth level of plunge working the linear position. The axial force increases the due to increase of the pressure at a higher extent the shoulder area will be stirred normal position easily.

## **4. Conclusions**

The present investigation shows the aluminum alloys with the application of Taguchi design of experiments helped us in conducting the experiments in an effective manner without losing accuracy. Two-dimensional plots are plotted between the input process parameter and the output responses using Design-Expert software. The tensile strength is increasing with the increase in rotational speed and the axial force values and the tensile strength is decreasing with the increase in the weld speeds. The impact strength increases, when there is an increase in the values of rotational speed and axial force. Whereas the impact strength tends to decrease with the increase in the weld speeds. The elongation also increases with the increase in rotational speed and axial force. The results presented in the work are analyzed on the basis of analysis process conducted with microstructures with different zones on thermo mechanical treatment zone has higher plasticity due to eutectic constituents Cu–Al precipitation on rolled condition and parent metal has rolled temper condition.

## **Author details**

Bazani Shaik1 \*, M. Muralidhara Rao1 , G. Harinath Gowd<sup>2</sup> , B. Durga Prasad3 and J. Ranga1

1 Ramachandra College of Engineering, Eluru, Andhra Pradesh, India

2 Madanapalle Institute of Technology and Sciences, Madanapalle, Andhra Pradesh, India

3 Jawaharlal Nehru Technological University, AnantapuramuAndhra Pradesh, India

\*Address all correspondence to: drbazanishaik@rcee.ac.in

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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## *Edited by Shashanka Rajendrachari*

This book is an important guide to aluminum alloys. It discusses the basics of aluminum alloys, how they are prepared, how their properties can be altered, the relationship between their microstructures and properties, and their advanced applications. This book includes eleven chapters organized into four sections: "Introduction to Aluminum Alloys", "Fabrication of Aluminum Alloys", "Properties of Aluminum Alloys", and "Advanced Applications of Aluminum Alloys". Chapters address such topics as aluminum alloys and their grain refinement; extrusion, low- and high-pressure casting, and additive manufacturing techniques to prepare different grades of aluminum alloys; how the property of aluminum alloys can be altered by adding dispersing agents; and more.

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Recent Advancements in Aluminum Alloys

Recent Advancements in

Aluminum Alloys

*Edited by Shashanka Rajendrachari*