Effect of Sc Alloying Additions on Structure and Mechanical Properties of PM and Cast High-Strength Al Alloys of same composition

摘要

High-strength wrought aluminum alloys of the same composition of Al-9.5Zn-3.OMg-1.2Cu were produced by PM and by melting. Alloys were doped with Sc and Zr in both cases. Rapidly solidified aluminum alloy powders were produced by high-pressure water atomization of the melt. The powder compacts cold pressed to about 30% porosity were subjected to hot vacuum degassing. On completing the degassing, the briquettes were consolidated by pulse pressing under a pressure of 1.0 GPa. The consolidated preforms were hot extruded to produce rods, which were heat treated. The addition of 0.2―0.3 wt.% Sc substantially increased the strength and plasticity characteristics of rods from melted alloys and to lower extent ―of rods from PM alloys, because highly dispersed structure in the latter is achieved already as a result of rapid solidification without doping by Sc. In all cases Sc increases the recrystallization temperature to 738 K or more.