Microstructure-property studies in spray formed Al alloys

摘要

A spray formed and forged Al-5Cr-1.5Zr (wt%) alloy was studied. The microstructure and tensile properties were evaluated, before and after forging, and cornpared to alloys of similar composition processed by a RS/PM route. The microstructure ofthe spray formed material consisted of clusters of Al{sub}13Cr{sub}2 intermetallics evenly distributed throughout the matrix. The coarse microstructure in the spray formed alloy was attributed to the cooling rates experienced during spray forming whichare lower than the cooling rates experienced by the powder particles in gas atomisation. The grain size of the spray formed alloy was an order of magnitude larger than the atomised and extruded alloy. The supersaturation of the a-Al matrix of the sprayformed material in Zr was at a lower level compared to the RS/PM allay. This resulted in poor ageing response and lower tensile properties.