In-depth investigation of microstructural evolution induced by Sc, V, and Ni microalloying in Al-Zn-Mg-Cu alloy during hot compression
Yuxin Dai, Liangming Yan, Song Sun, Jingyu Zhang, Xinhao Li, Juncheng Liu, Xuefang Liu
Abstract
• V and Ni addition boosts peak peak power dissipation (ν) to 41% (35% in Al-Zn-Mg-Cu-Sc). • V and Ni increase precipitate volume fraction, reduce size. • V and Ni addition enhance flow stress above 420°C through HCP-Al 7 Cu 4 Ni and FCC-Al 21 V 2 phases. • At 440°C/0.01 s −1 , V and Ni promote 1/6〈112〉 partial and (111)[110]/[001] perfect dislocations. This study explores the microstructural changes and mechanical behavior of an Al-Zn-Mg-Cu-Sc-(V-Ni) alloy during hot compression, conducted at temperatures ranging from 340 to 460°C and strain rates from 0.01 to 10 s −1 . Molecular dynamics simulations were employed to examine dislocation evolution and mechanical behavior. The peak power dissipation values (ν) for the Al-Zn-Mg-Cu-Sc and Al-Zn-Mg-Cu-Sc-V-Ni alloys were 35 % and 41 %, respectively, reflecting enhanced energy dissipation with V and Ni additions. The second-phase strengthening effects of Al 7 Cu 4 Ni (HCP-type) and Al 21 V 2 (FCC-type) significantly increased the high-temperature flow stress of alloy. During hot compression of the Al-Zn-Mg-Cu-Sc-V-Ni alloy, typical (111)[110] and (111)[001] perfect dislocations were observed. The accumulation of dislocations facilitated diffusion pathways, accelerating the precipitation of the η-MgZn 2 phase. The addition of Sc, V, and Ni increased the number of 1/6 < 112 > Shockley partial dislocations and 1/2 < 110 > Perfect dislocations at elevated temperatures, thereby enhancing the alloy’s compression resistance.