Research Of The Mechanical Property Of New Magnesium Alloy Mg-3.5Y-0.8Ca-0.5Zr

As the eruption of engergy crisis in the world, aircraft, cars, etc, high energy-intensity machines'requirements to the light material is more and more prominent. Mg alloy which gets great attention has become the focus of national contest of the material's research and development. As the ignition-proof magnesium alloy Mg-3.5Y-0.8Ca has low mechanical properties, This paper studied the microstructure of Mg-3.5Y-0.8Ca-0.5Zr with the optical microscope, the microscopic elements'changes in as-cast, and natural aging, quenching processing, cold rolling, solid solution after cold rolling, respectively, the main results are as follows:(1) Refine grains with Zr instead of Mg for heterogeneous nucleation after adding 0.5% Zr to the Mg-3.5Y-0.8Ca flame-retardant magnesium alloy. But the mechanical properties are low. The case is that rare earth elements'easily segregated led to the elements'component added segregation. (2) To a certain degree, mechanical properties improved in natural aging. The case is that the organization became more uniform with the alloy element, which are originally segregated from the grain boundary, evenly dispersed into the grain after the atomic' diffusion.(3) After solid solution respectively at 450℃and 470℃for 5h, alloy's mechanical performance substantially improved with the elements on the grain boundary more homogenously scattered into grains, which made grain a slight growth. The 470℃solid solution for 5h is a better quenching process with the grain size more uniformly, solid solution higher, elongation higher. Relative to the treatment of natural aging, alloy's mechanical properties was slightly lower. The reason may be that the influence of grain's growth is greater than that of the elements'uniformity.(4) After cold rolling, alloy's mechanical performance was improved in a large scale. with the elements on the grain boundary more homogenously scattered into grains. The reason may be that the interaction of recrystallizationin the process of annealing and the force made the grains and the elements'distribution become more uniform, is relatively uniform.(5) Relative to cold rolling, the mechanical properties of the alloy got slightly improvement. The ultra tensile strength and the elongation rate respectively increased to 266MPa and 16.9%. The reason may be that solid solution after cold rolling, make the elements more uniform.