TY - JOUR
T1 - Investigation on the enhanced maximum strain rate sensitivity (m) superplasticity of Mg-9Li-1Al alloy by a two-step deformation method
AU - Yang, H.P.
AU - Zhang, Xiaobo
AU - Chen, Peng
AU - Fu, Mingwang
AU - Wang, Gaochao
AU - To, Suet
PY - 2019/9/9
Y1 - 2019/9/9
N2 - A two-step superplastic deformation (SPD) approach was employed for the SPD of Mg-9Li-1Al (LA91) alloy. In the first SPD step, the constant velocity (Constv) or constant strain rate (CSR) SPD was adopted with the outcome elongation ranging from 50 to 250%. The maximum strain rate sensitivity (Maxm) SPD, in which the maximum m value is always maintained, was then employed in the second SPD step. The results show that the two-step SPD can greatly enhance the superplasticity of LA91 alloy. The largest elongation of 621.1% was obtained by CSR-Maxm SPD with the pre-elongation of 250%, which is even better than the results of single-step Maxm SPD by using grain-refined materials. In addition, the mechanisms of the two-step SPD are discussed and an in-depth understanding of the SPD of LA91 alloy is obtained. This research thus provides a feasible method for efficiently enhancing the plasticity of Mg-Li based alloys for making complex parts and structures with complicated local and multi-scaled features.
AB - A two-step superplastic deformation (SPD) approach was employed for the SPD of Mg-9Li-1Al (LA91) alloy. In the first SPD step, the constant velocity (Constv) or constant strain rate (CSR) SPD was adopted with the outcome elongation ranging from 50 to 250%. The maximum strain rate sensitivity (Maxm) SPD, in which the maximum m value is always maintained, was then employed in the second SPD step. The results show that the two-step SPD can greatly enhance the superplasticity of LA91 alloy. The largest elongation of 621.1% was obtained by CSR-Maxm SPD with the pre-elongation of 250%, which is even better than the results of single-step Maxm SPD by using grain-refined materials. In addition, the mechanisms of the two-step SPD are discussed and an in-depth understanding of the SPD of LA91 alloy is obtained. This research thus provides a feasible method for efficiently enhancing the plasticity of Mg-Li based alloys for making complex parts and structures with complicated local and multi-scaled features.
KW - Two-step superplastic deformation
KW - Constant velocity SPD
KW - Constant strain rate SPD
KW - Maximum strain rate sensitivity (m) SPD
KW - Mg-Li alloy
U2 - 10.1016/j.msea.2019.138219
DO - 10.1016/j.msea.2019.138219
M3 - Journal article
SN - 0921-5093
VL - 764
JO - Materials Science and Engineering A
JF - Materials Science and Engineering A
M1 - 138219
ER -