Effect of Heat Treatment on the Microstructure of Mg-4Al-Nd Alloys

Author： Mishra Sibani Chaubey Anil Mandal Animesh

Publisher： MDPI

E-ISSN： 2227-7080|5|2|23-23

ISSN： 2227-7080

Source： Technologies, Vol.5, Iss.2, 2017-05, pp. : 23-23

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Abstract

In the present work, Mg-4Al-xNd (x = 0, 1, 4 wt.%) alloys were prepared by a stir casting method, and the effect of the addition of Neodymium (Nd) as-cast and of heat-treated microstructures was studied. The addition of 1 wt.% Nd preferentially formed the Al₂Nd phase and completely suppressed the formation of the intermetallic Mg₁₇Al₁₂ (γ) phase, which was initially present in the base alloy (Mg-4Al alloys). On increasing the Nd percentage from 1 to 4 wt.% in the base alloy, two intermetallic phases, Al₂Nd and Al₁₁Nd_3, were observed in the microstructure, as higher levels of Nd led to a peritectic reaction between Al and the Al₂Nd phase, and part of the Al₂Nd transformed into the Al₁₁Nd₃ phase. The hardness of the as-cast alloy increased with the Nd content. Thus, the hardness increased from 57.1 ± 4.1 Hv of Mg-4Al to 66.5 ± 2.6 Hv of Mg-4Al-4Nd. It was also found that solutionizing and isothermal aging of alloys containing Nd at 180 °C for 96 h led to the size reduction of Al- and Nd-containing intermetallics without altering their morphologies. Further, it was found that Nd does not have any effect on the aging kinetics of the alloys because all of the alloys with and without Nd attained peak hardness at 24 h of aging time.