Synergistic effect of LPSO and eutectic phase on mechanical properties of Mg-Gd-Nd-Zn-Zr alloy during equal channel angular pressing

In this paper, the homogenized Mg-9Gd-2Nd-1.6Zn-1Zr (wt%) alloys were subjected to various equal channel angular pressing (ECAP) passes (1, 2, 4 and 8) with Bc route at 400 degrees C. Then, the microstructure evolution and strengthening mechanisms of alloys were systematically investigated. The results show that the coarse deformed grains are completely consumed by the dynamic recrystallized (DRX) grains, the number of dynamic precipitates gradually increases, and the intensity of basal texture of the alloy is gradually weakened with increasing ECAP passes. After 8 passes ECAP, the grain size is dramatically refined from 50 mm (homogenized) to 2.1 mm (8p-ECAPed), which is mainly due to the DRX, particle stimulated nucleation (PSN) induced by broken eutectic phase and hinder grain growth of dynamic precipitates. The excellent comprehensive mechanical properties are achieved by 4 passes, and the corresponding yield strength (YS) and ultimate tensile strength (UTS) as well as elongation (EL) are 321 MPa, 378 MPa and 14.4%, respectively. This can be mainly ascribed to the combined effect of broken eutectic phase, DRX grains, kinked long period stacking order (LPSO) and dynamic precipitates. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

In this study, the microstructure evolution and strengthening mechanisms of homogenized Mg-9Gd-2Nd-1.6Zn-1Zr alloys subjected to various equal channel angular pressing (ECAP) passes were systematically investigated. After 8 ECAP passes, the grain size was dramatically refined, while excellent mechanical properties were achieved after 4 passes.