挤压温度对高硅铝合金材料力学性能的影响

Effect of Extrusion Temperature on Mechanical Properties of High-silicon Aluminum Alloy

针对航空航天电子封装用轻质高硅铝合金材料,采用空气雾化水冷与真空包套热挤压工艺相结合的方法,制备了 Al-30Si 和 Al-40Si 过共晶高硅铝合金材料,并通过金相显微镜观察了材料的微观组织,测定了合金材料的抗拉强度以及延伸率,对拉伸试样的断口进行了扫描。探讨了挤压温度对材料组织、强度、延伸率及断裂行为的影响。结果表明:利用粉末冶金热挤压技术所制备的高硅铝合金材料,其硅相细小,当挤压温度为370℃时,其硅相大小为2～10μm,且分布均匀弥散;硅相尺寸随着挤压温度的升高而长大;抗拉强度随挤压温度的升高而降低.Al-30Si 经370℃挤压后,其室温抗拉强度为239MPa,而550℃为206MPa;延伸率随挤压温度的升高而有所增加,但不很敏感;随挤压温度的升高,材料的断裂方式由单纯的韧性断裂逐渐向韧性与脆性共存的混合断裂方式转变。

Light weight Al-30Si and Ai-40Si used for e ectronic packaging in the aviation and space-flight are fabricated with a method in which air-atomization is followed by vacuum canning hot-extrusion process.Microstructure is analyzed through optical microscopy,tensile strength,ductility and SEM fracture surface are also examined.Experi- mental results show that Si particles in high-silicon aluminum alloy are 2～10μm at 370℃ extrusion temperature and distribut uniformly;Si particle size becomes larger with extrusion temperature increase;the tensile strength decreases with extrusion temperature increase;it reaches 239 MPa extruding at 370℃ and 206MPa at 550℃;ductility increases with extrusion temperature increase,but it is not sensitive;The fracture mode of the material changes gradually from tough fracture mode to a mixture of tough and brittle ones with the increase of extrusion temperature.