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研究了往复挤压对铸造Mg-6%Si(质量分数,下同)合金微观组织和力学性能的影响。结果表明:往复挤压4道次后,Mg-6%Si合金的显微组织得到显著细化,粗大树枝状的初生Mg2Si相变为细小颗粒状,而汉字状的共晶Mg2Si相也变为弥散分布的点状相,且这些颗粒状的Mg2Si相均匀分布在基体中。往复挤压4道次后,Mg-6%Si合金的抗拉强度和延伸率分别提高了82.3%和810.9%。断口分析表明,往复挤压合金的断裂模式由脆性断裂转变为韧-脆性断裂。
The effect of reciprocating extrusion on the microstructure and mechanical properties of the as-cast Mg-6% Si (mass fraction) alloy was studied. The results show that the microstructure of Mg-6% Si alloy is significantly refined after reciprocating extrusion for 4 passes, the coarse dendritic primary Mg2Si phase changes into small granular shape, and the Chinese character eutectic Mg2Si phase also becomes Dispersed dispersed dot phase, and these granular Mg2Si phase evenly distributed in the matrix. After 4 times reciprocating extrusion, the tensile strength and elongation of Mg-6% Si alloy increased by 82.3% and 810.9% respectively. Fracture analysis shows that the fracture mode of reciprocating extrusion alloy changes from brittle fracture to ductile-brittle fracture.