EFFECT OF EXTRUSION CONDITIONS ON MECHANICAL-PROPERTIES OF AL-20SI-3CU-1MG ALLOY PREPARED FROM RAPIDLY SOLIDIFIED POWDER

A study on the optimization of extrusion conditions for a prospective Al-20Si-3Cu-1 Mg alloy prepared from rapidly solidified powder was carried out by evaluating tensile properties at room and elevated temperatures. It was found that extrusion conditions influence the as-extruded microstructure and mechanical properties of the alloy to a certain extent. The relationship between the as-extruded mechanical properties and such extrusion variables as temperature, reduction ratio and die shape, can be described by using temperature-compensated strain rate, so that the as-extruded properties can be tailored in a certain range by adjusting this process parameter. In addition, the comparison between the as-extruded and as-T6 tempered tensile properties at elevated temperatures has opened the question as to the necessity of applying the heat treatment to the alloy - a normal practice subsequent to the extrusion. The experimental results suggest that for the material used at temperatures at and above 200-degrees-C, the T6 temper treatment can be eliminated.