**2.2 Equal channel angular extrusion**

Die-Material: Hot Die steel (HDS) was used for die making. The ECAE die design was done by using solid edge V.7 software and fabrication was carried out at Government Tool Room and Training Centre (GTTC) Baikampady, Mangalore, Karnataka, India. **Figure 3** depicts the ECAE die having 900 and 1100 channel angle

**Figure 1.** *AZ80 Mg alloy (a) microstructure (b) EDS results.*

*Effect of ECAE Die Angle on Microstructure Mechanical Properties and Corrosion Behavior… DOI: http://dx.doi.org/10.5772/intechopen.94150*

**Figure 2.** *AZ91 Mg alloy (a) microstructure (b) EDS results.*

**Figure 3.**

*ECAP die having 900 and 1100 channel angle and 300 corner angle (Naik et al. Copyrights: Diary number: 14668/2018-CO/L., Reg. No: L-79923/2018).*

and 300 corner angle. An equal channel angular extrusion thermo-mechanical apparatus is provided grain refinement to improve mechanical properties and corrosion resistance of magnesium alloys. ECAE is promising extrusion technique to achieve ultra-fine equiaxed grains without changing the shape of the workpiece. The extrusion die assembly having two angles such as channel angle (*ϕ*) and corner angle (*ψ*) which decides the induced shear strain during ECAP. Current study focusses on the effect of ECAE die angles on microstructure, mechanical properties and corrosion resistance of AZ80/91 Mg alloys. In the present study route, *R* was considered to deform the material to achieve a fine grain structure. Route *R*: the specimen is inverted to the original position in each ECAP passes. The experimental setup of equal channel angular extrusion is shown in **Figure 4**. During operation ECAP die (**Figure 4**) is placed on the base plate of UTM and plunger is aligned exactly to the center of die where the specimen is placed inside the channel for pressing. The sample is placed in the die channel and needs to make sure that the temperature of the specimen also reached the 598 K.

A lubricant as Molybdenum disulfide (MoS2) was used to minimize the frictional effects between samples and die. After attaining the required

**Figure 4.** *Equal channel angular extrusion experimental setup.*

#### **Figure 5.** *(a) Route-R and (b) ECAPed sample.*

temperature, the sample is pressed by applying a load at the rate of 1 mm/sec ram speed using plunger attached to the UTM for deformation of the specimen. The channels are intersected to impose the total strain on the material to get a fine grain structure. This process is repeated by using route R, where the samples were inverted from its initial position between two successive passes as shown in **Figure 5(a)**. The processed samples after ECAP operation is shown in **Figure 5(b)** [7–12].
