Effects of the thixocasting injection velocity on tensile properties of an A357 Al alloy

In this study, the effects of injection velocity on tensile properties and hardness of A357 aluminum alloy produced by thixocasting process were investigated. For this purpose, feedstock produced by cooling slope process were first held at reheating temperature of 572 degrees C and then formed at injection velocities of 1, 1.5, 2 and 2.37 m x s(-1), respectively. In order to make comparisons, other specimens were produced by high pressure die casting method via melted metal at the casting temperature of 630 degrees C using same injection velocities. Tensile test and hardness measurements were conducted for all specimens. The best tensile test properties were obtained for the specimens produced by thixocasting process at injection velocity of 2.37 m x s(-1). For this specimens, the values of 0.2 % proof strength, tensile strength and total elongation were obtained as 89.9 MPa, 237.3 MPa and 20.7 %, respectively. Furthermore, its hardness were measured as 74 HV.