Study on microstructures and mechanical properties of plaster mould casting aluminum alloy under the condition of vacuum pressurizing solidification and vacuum solidification

Microstructures and mechanical properties of plaster mould casting aluminum alloy ZL105A under the condition of vacuum pressurizing solidification and vacuum solidification were studied. The results show that there is no effect on phase composition of solidification microstructures, the α(Al) crystal grain was refined of sample solidified under pressure, the second phase distribution more homogenized, the feeding capacity and microstructures density were improved, the shrinkage porosity was decreased. Meanwhile, tensile strength and yield strength of the experimental alloy was improved, and there is no apparent effect on plastic properly. Tensile strength and yield strength of the experimental alloy decreased with the increase of the size of specimen under the same condition, but plasticity was increased slightly. The size effect of mechanical properties for the experimental alloy was more obvious for the case under the condition of vacuum pressurizing solidification.