Technical basis of using laser direct energy deposition as a high-throughput combinatorial method for DC-cast Al-Mn alloy development
Qingyu Pan, Monica Kapoor, Sean Mileski, John E. Carsley, Xiaoyuan Lou
Abstract
This work evaluated the technical basis of using laser direct energy deposition (DED) additive manufacturing (AM) as a rapid alloy screening method to study the phase transformation of second phase particles and recrystallization behavior of Al-Mn alloy AA3104 throughout the steps of thermomechanical processing. The study focused on assessing the differences between DED and DC-cast AA3104 alloy after homogenization and hot rolling. The fast cooling and repeated in situ thermal cycles during DED AM resulted in different phase transformation behavior compared to conventional DC-cast alloys. DED alloys exhibited a higher fraction of α-Al (Fe,Mn)-Si particles, more uniform particle distribution, and stronger cube texture in the as-fabricated condition. Homogenization promoted Al6(Fe,Mn) to α-Al (Fe,Mn)-Si phase transformation in both DED and DC-cast alloys. After homogenization, DED alloys exhibited two times as many coarse α particles in area fraction as DC-cast alloys but fewer nanoscale dispersoids. These unique material characteristics in DED alloys were responsible for easier recrystallization after hot rolling and annealing. While the differences existed, DED and DC-cast AA3104 alloys demonstrated a similar trend in phase transformation and recrystallization, strongly reinforcing that DED AM can support high-throughput Al alloy development.