Correlation of milling time with phase evolution and thermal stability of Mg-25 wt%Sn alloy

Mg-25Sn (wt%) mixtures were prepared by mechanical alloying (MA), and then cold-compacted into preforms. Correlation of milling time with phase evolution during MA and their thermal stability in the subsequent heating-up process was investigated. The raw nano-sized Sn powder is conductive to the accelerated synthesis of Mg2Sn phase, by which nano cubic and hexagonal Mg2Sn could be obtained after 5 h and 20 h MA, respectively. During the heating process, the residual Sn in the short-time ball milling (5 h, 10 h) transforms mainly into Mg2Sn bulk through melting and subsequent diffusion reactions. However, the 20 h MAed mixture has experienced inverse eutectic and subsequent thixotropic reactions, in which metastable-to-equilibrium transition of Mg2Sn occurs. Mg2Sn phase formed in the two cases are nanosized. A uniform dispersion of fine Mg2Sn phase and the retention of inverse eutectic liquid phase primarily account for the improvement in mechanical properties of the sintered material. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Through mechanical alloying, Mg2Sn phase with different structures can be obtained at different milling times in Mg-25Sn mixtures, leading to the improvement of mechanical properties in sintered materials.