**6. References**

Bäckerud, L. & Chai, G. (1992). Solidification Characteristics of Aluminum Alloys 3, American Foundry Society, Des Plaines, Illinois

Currently, efforts are being directed towards the development of analytical techniques which rapidly achieve an accurate determination of phase components in an alloy. According to the obtained results, the applicability of the proposed methods provides a practical alternative to other techniques. The phenol extraction procedure was also successfully applied to the examined aluminium alloys. The main advantages of dissolution techniques are its reliability – when used properly you will always get pure residue – and its low price. The major disadvantageous of phenol extraction method are the possible

The examined alloys AlSi5Cu1Mg and AlCu4Ni2Mg2 possessed a complex microstructure. By using various instruments and techniques (LM, SEM-EDS, TEM and XRD) a wide range of intermetallics phases were identified. The microstructure of investigated AlSi5Cu1Mg alloy included: β-Al5FeSi, α-Al12(FeMn)3Si, Al2Cu, Q-Al5Cu2Mg8Si6, Si and Mg2Si phases. The microstructure of AlCu4Ni2Mg2 alloy included five phases, namely: Al7Cu4Ni, θ′-Al2Cu, Al6Fe, S-Al2CuMg, and Al3(CuFeNi)2. A size and distribution of these various dispersoids depend on the time and temperature of the homogenization and/or annealing processes. Fine intermetallic particles (<lμm) are formed during artificial aging of heat-treatable alloys and are more uniformly distributed than constituent particles or dispersoids. Dimensions, shape and distribution of these particles may have important effects on the ductility of alloys and more needs to be known regarding their formation, structure and composition. For example, the coarse particles can influence the recrystallization, fracture, surface, and corrosion behavior, while the dispersoids control grain size and provide stability to the metallurgical structure. The dispersoids can also affect the fracture performance and may limit strain localization during deformation. The formation of particles drains solute from the matrix and, consequently, changes the strength properties of the material. This is specially relevant in the heat-treatable alloys, where depletion in Cu, Mg, and Si can significantly change the metastable precipitation processes and age hardenability of a material. Therefore, particle characterization is essential not only for choosing the best processing routes, but also for designing optimized alloy composition. Thus, particle characterization is important not only to decide what sort of processing courses should be applied, but also for designing optimized chemical composition of a material. A variety of microscopic techniques are well appropriate to characterize intermetallics but only from a small section of an analyzed sample. From commercial point of view it is extremely advantageous to provide use quick, reliable and economical examination technique capable of providing data of particles from different locations of a full scale-sized ingot. One of these methods is dissolving the matrix of an aluminium alloy chemically or electrochemically.

This work was carried out with the financial support of the Ministry of Science and Higher

Bäckerud, L. & Chai, G. (1992). Solidification Characteristics of Aluminum Alloys 3,

**4. Conclusion** 

**5. Acknowledgment** 

**6. References** 

Education under grant No. N N507 247940

American Foundry Society, Des Plaines, Illinois

contamination of the residue and the time needed.


**3** 

Akira Watazu

Metallic material

*Japan* 

**Rotary-Die Equal Channel** 

**Angular Pressing Method** 

*National Institute of Advanced Industrial Science and Technology (AIST)* 

Die

Light metals such as aluminum, magnesium, titanium and their alloys are useful for a wide range of applications such as in the automotive, railway, and aerospace industries. Engineering of fine-grained light metal materials is an indispensable technology that is expected to improve material properties such as tensile strength, elongation, corrosion resistance, fracture toughness, strain-rate plasticity, low-temperature plasticity, etc. The production of fine-grained light metals with excellent properties using severe plastic deformation methods, especially rolling and extrusion, has been intensively studied. With such processes, the size of the metal grain generally decreases because plastic deformation

b)

On the other hand, the equal channel angular pressing (ECAP) method invented by Segal et al. in 1981 has proven successful for fabricating fine-grained bulk metals. A schematic diagram of the ECAP method is shown in Fig. 2. In the ECAP method, a large strain can be introduced into a billet sample by simple shear deformation without changes in the crosssectional area. In the ECAP process, the billet is extruded through a die consisting of two channels intersecting at an angle of 2Φ. The sample is set in the vertical channel and pressed into the second channel. The greatest advantage of the ECAP method is that the initial size

causes a decrease of grain size, by the principle shown schematically in Fig. 1.

Fig. 1. Schematic diagram of a) rolling method and b) extrusion method

**1. Introduction** 

a)

Metallic material

Roll

