摘要
The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry, which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys. For advanced engineering design of light magnesium automotive applications, it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys. In this study, magnesium alloy AM60 with different section thicknesses of 6, 10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated. The prepared squeeze cast AM60 specimens were tensile tested at room termperature. The results indicate that the mechanical properties including yield strength （YS）, ultimate tensile strength （UTS） and elongation （A） decrease with an increase in section thickness of squeeze cast AM6O. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness. The numerical simulation （Magmasoft） was employed to determine the solidification rates of each step, and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness. The computed solidification rates support the experimental observation on grain structural development.
The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry,which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys.For advanced engineering design of light magnesium automotive applications,it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys.In this study,magnesium alloy AM60 with different section thicknesses of 6,10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated.The prepared squeeze cast AM60 specimens were tensile tested at room termperature.The results indicate that the mechanical properties including yield strength(YS),ultimate tensile strength(UTS)and elongation(A)decrease with an increase in section thickness of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness.The numerical simulation(Magmasoft)was employed to determine the solidification rates of each step,and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness.The computed solidification rates support the experimental observation on grain structural development.
