Microstructure,mechanical property and thermal conductivity of Mg-6Gd-1Er-6Zn-0.5Zr alloy sheets
Magnesium(Mg)alloys with integrated structural-functional performance have broad applications in the fields of defense and military industry,transportation and electronic communication,etc.Developing Mg alloy sheets with synergistic mechanical property and thermal conductivity is a key to achieving these applications.The effects of rolling temperature and cumulative strain on the microstructure evolution and mechanical property and thermal conductivity of solid-solution Mg-6Gd-1Er-6Zn-0.5Zr(mass fraction,%,GEZ616K)alloy were investigated.The results show that,as the rolling temperature increasing,the microstructures of the sheet with cumulative deformation strain of 80%undergo transformation process from mixed crystallization at low-temperature to uniform fine recrystallization and grain coarsening at high temperature.At the same time,the basal texture weakens,the proportion of large angle grain boundary increases,and dislocation density in the alloy decreases.At a certain rolling temperature,the number of twins gradually decreases and the proportion of recrystallization gradually increases with the increase of the cumulative strain,resulting in a synchronous improvement of mechanical property and thermal property.The GEZ616K alloy rolled at 425 ℃ with cumulative strain of 80%exhibits the excellent mechanical property and thermal property,the tensile strength,yield strength and elongation are 280 MPa,227 MPa and 11.4%,respectively,as well as the thermal diffusion coefficient of 72.9 mm2/s and the thermal conductivity of 135.3 W/(m·K).
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