Improved workability for Mg-Y-Zn alloys via increased volume fraction of block LPSO phases

Abstract

As one aspect of LPSO morphology, the volume fraction of block LPSO phases (VFLPSO-B) was tailored by changing the total content of solute atoms in Mg-Y2x-Znx (x = 1, 0.5, and 0.25 at.%) alloys. The effects of VFLPSO-B on compression behavior, dynamic recrystallization (DRX), and workability were investigated. The results reveal that increasing VFLPSO-B leads to higher flow stress, hardness, DRX ratio, and better workability which is embodied in the lower deformation activation energy (Q), broader deformable conditions, and narrower improper processing domains. Kink bands and initial grain boundaries are ideal sites for the nucleation of DRX grains during compression. Block LPSO phases near the initial grain boundaries further promote the nucleation of DRX grains but inhibit their growth, which contributes to increasing the DRXed grain size exponent (m). This paper reveals the feasibility of improving the workability of LPSO-containing Mg alloys by modifying the LPSO morphology to broaden their applications.