半固态挤压铸造镁合金坯料组织与性能研究

Microstructure and Properties of Semi-solid Magnesium Alloy feedstock Prepared by Squeeze Casting

采用双螺杆机械搅拌法制备半固态镁合金浆料,研究了半固态挤压铸造成形坯料不同部位的组织与性能。结果表明,坯料组织中初生α相呈现不规则的多边形或蔷薇状结构,其晶粒平均直径为45~65μm。坯料边缘和中心部位的组织结构明显不同,边缘处的组织更细小。半固态挤压铸造成形工艺在提高铸件致密度的同时,也提高了铸件的硬度,与液态挤压铸造成形试样相比,其密度提高了0.33%,硬度提高了4.78%。

Based on the semi-solid slurry was prepared by twin-screw stirring,the microstructure and properties of semi-solid magnesium alloy feedstock formed by squeeze casting was investigated.The results show that the structure of primary α-Mg phase in feedstock is polygon or rosette,and the average size of grains is 45 μm^65 μm.The structure of primary α-Mg in the edge and the center of feedstock is different,and the grain size of feedstock edge is finer.Meanwhile,the density and hardness of semi-solid feedstock of magnesium alloy are increased in comparison with the sample fabricated by liquid squeeze casting,the density and hardness are increased by 0.33%and 4.78%,respectively.