Evolution of LPSO Structure of Mg-11Gd-4Y-2Zn-0.5Zr Alloy during Hot Compression Deformation at Different Temperatures

Abstract

The deformation behavior and microstructure evolution of LPSO phase of Mg-11Gd-4Y-2Zn-0.5Zr magnesium alloy were investigated. This alloy was deformed by hot compression using Gleeeble 3500 thermal simulation machine at different temperatures. The microstructure was analyzed by optical microscopy (OM), scanning electron microscopy (SEM) with spectroscopy (EDS) and XRD. The results showed that the kink bands of LPSO structure of Mg-11Gd-4Y-2Zn-0.5Zr alloy, after thermal compression processing, aggravated as temperature increasing. The fine lamellar LPSO phase could be observed in the alloy. At 450 °Cand 500 °C, some fine lamellar LPSO phase in the grain had been broken into short rod or small block forms, meanwhile, a new rod-like LPSO structure appeared along the grain boundary. Moreover, the decomposition of LPSO structure was more obvious with the increasing of temperature. During hot compression deformation, the segregation of Y, Zr had eliminated partially and the diffraction peaks of W-phase had disappeared. Moreover, there was an increase in hardness as the dispersion distribution of LPSO phase increased.