Length scale of the dendritic microstructure affecting tensile properties of Al–(Ag)–(Cu) alloys

Abstract

The dependence of tensile properties on the length scale of the dendritic morphology of Al–Cu, Al–Ag and Al–Ag–Cu alloys is experimentally investigated. These alloys were directionally solidified (DS) under a wide range of cooling rates [Formula: see text], permitting extensive microstructural scales to be examined. Experimental growth laws are proposed relating the primary dendritic arm spacing, [Formula: see text] to [Formula: see text] and tensile properties to [Formula: see text]. It is shown that the most significant effect of the scale of [Formula: see text] on the tensile properties is that of the ternary alloy, which is attributed to the more homogeneous distribution of the eutectic mixture for smaller [Formula: see text] and by the combined reinforcement roles of the intermetallics present in the ternary eutectic: Al2Cu and nonequilibrium Ag3Al.