Strength-ductility synergy in Mg98.3Y1.3Ni0.4 alloy processed by high temperature homogenization and rolling

A new Mg98.3Y1.3Ni0.4 alloy containing long period stacking ordered (LPSO) phases with good strength-ductility synergy was prepared by high temperature homogenization and rolling, which possesses a high ultimate tensile strength of 320 MPa and elongation of 17.0% and low work hardening rate during ten-sile deformation. Bulk LPSO phases with lamellar morphology exist in original grains after homogeniza-tion. Refined grains, broken LPSO phases and high-density geometrically necessary dislocations provide a good strength for as-rolled alloy with the strength increment of 146.3 MPa, 51.7 MPa and 68.3 MPa, respectively. Good ductility and low work hardening rate are attributed to weak basal texture, activation of non-basal slips with high Schmid factors and annihilation of high-density dislocations. In situ tensile testing result shows deformation coordination by non-basal slips, deformation twinning, grain rotation and absorption of plastic deformation energy by LPSO phases, which suggests a good ductility as well. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

A new Mg98.3Y1.3Ni0.4 alloy with good strength-ductility synergy, high ultimate tensile strength, and low work hardening rate has been prepared through high temperature homogenization and rolling. The strength increment in the alloy is attributed to refined grains, broken LPSO phases, and high-density geometrically necessary dislocations. The good ductility and low work hardening rate are due to weak basal texture, activation of non-basal slips with high Schmid factors, and annihilation of high-density dislocations.