等通道转角挤压对铝硅合金的硅形态及力学性能的影响

摘要

采用等通道转角挤压工艺(ECAP)对两种铸造铝硅合金(ZL101和ZL102)进行不同道次的加工，研究晶粒细化及硅形态对合金力学性能的影响。结果表明：多道次ECAP能有效细化针状共晶硅相并改善其在铝基体中分布的均匀性，具有尺寸细小、分布弥散且棱角钝化共晶硅的铝硅合金具有更优的力学性能；铸态合金ECAP加工后强度和韧性均获提高，固溶+16道次ECAP加工后ZL102合金的伸长率和抗拉强度约为铸态的5.04倍和1.39倍；随挤压道次的增加，两种合金的断裂方式均由脆性断裂向韧性断裂转变；固溶后挤压可获得优良的强韧组合，满足制造行业需要。%Two casting Al-Si alloys(ZL101 and ZL102) were processed by multi-pass equal-channel angular pressing (ECAP) for grain refinement, and the effects of morphology change of Si particles on their mechanical behaviors were studied. The results show that ECAP could effectively reduce the size of needle-like eutectic silicon and homogeneously disperse it in the Al matrix. The alloy with small and obtuse silicon particles dispersed in the Al matrix has better mechanical behaviors. ECAP can simultaneously improve the strength and plasticity of the as-cast alloys. The elongation and the tensile strength of the ZL102 alloy after solution-treatment plus 16 ECAP passes are 5.04 and 1.39 times as much as those of the as-cast sample, respectively. With the increase of the pressing pass, the fracture mechanism of two alloys changes from brittle fracture to ductile fracture. The combination of solution treatment and ECAP can obtain excellent strength and plasticity of the Al-Si alloys, which can meet the needs of manufacturing industry.