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.

Microstructure and Tensile Strength of an Al-Si-Fe-V Alloy: Vanadium and Solidification Thermal Parameters as Recycling Strategies

“…The primary (λ 1 ) and secondary (λ 2 ) dendrite arm spacings are plotted versus the solidification thermal parameters in Figures 12 and 13, respectively. Note that the exponents were set to be the same values previously reported for several Al-based alloys, i.e., −0.55 and −1.1 exponents in experimental laws to correlate λ 1 with cooling rate and growth rate, respectively, and −1/3 and −2/3 to correlate λ 2 with cooling rate and growth rate, respectively, which proved to be effective for several binary and ternary alloys solidified under unsteady-state conditions [31][32][33]. Interestingly, the conclusions are the same either using the equation with liquidus or with average thermal parameters.…”

Intrinsic and Extrinsic Effects of Microstructure on Properties in Cast Al Alloys

“…The dendrite arm spacing-elongation (e F ) relationship follows a Hall-Petch-type Equation (2) [58][59][60][61], such that:…”

On the statistical distribution of primary and secondary dendrite arm spacing in cast metals

“…In cast metals, dendrite arm spacing provides better correlation with mechanical properties than grain size does [1]. In directionally solidified alloys, primary dendrite arm spacing (λ 1 ) and secondary dendrite arm spacing (λ 2 ) have been used to develop correlations with tensile strength and elongation [2][3][4]. Secondary dendrite arm spacing has been reported as a measure that defines the microstructure in equiaxed microstructures and even has been proposed as a measure of casting quality [5].…”