1998 Volume 48 Issue 4 Pages 168-173
The aim of this study is to determine optimum forging conditions for Mg–Gd–Nd–Zr and Mg–Gd–Y–Zr alloys. Firstly, homogenization temperature of these alloys was altered at the solvus temperature, above and below that temperature to evaluate the effect of grain size and remained compound on high temperature deformation characteristics by conducting high temperature tensile and compression tests. Consequently, an increase in elongation is obtained in specimens with both a small amount of compound and a small grain size. However, the prevention of grain coarsening is found to be a more important factor for the increase in elongation of these specimens than the amount of compound. As a next step, these specimens controlled the grain size more than 65 μm were used for die forging into a piston shape under the conditions of a die speed of 0.36 to 0.41 m/s, a specimen temperature of 500°C and a mold temperature of 300°C. Applying these optimum forging conditions leads to the production of die-forged pistons with an excellent surface finish and without internal cracks.
