挤压变形对粉末冶金Al-Si-Cu合金组织和性能影响

Effects of Extrusion Deformation on Microstructure and Properties of Al-Si-Cu Alloy Produced by Rapid Solidification and Powder Metallurgy Methods

利用金相观察、SEM和XRD等方法研究了生坯挤压并在N2气氛下烧结制备的Al-Si-Cu合金的微观组织,并测试了其力学性能。结果表明,Al-Si-Cu合金生坯经过挤压后,致密度增加,Si和Cu的晶粒均匀分布在Al基体中,无明显界面。其物相组成为α-Al、β-Si、Al2O3、CuAl2和Cu4Si,其中CuAl2和Cu4Si是在挤压后烧结过程中形成。合金力学性能显著提高,其硬度(HV)、抗拉强度和伸长率分别为71.5、400 MPa和13.8%,断口形貌从典型的冰糖状脆性断口转变为含有韧窝的塑性断口。

The microstructure and phase structure of the Al-Si-Cu alloy prepared by the extrusion combined with N2 sintering were investigated by metallographic,SEM and XRD,and mechanical properties of the alloy were measured.The results show that after extrusion,the relative density of the alloy is increased as a result of the decrease of gas hole,and the grains of the Al and Cu are distributed homogenously in the Al matrix with absence of obvious interface.The phase structure is composed ofα-Al,β-Si,Al2 O3,CuAl2 and Cu4 Si,in which the CuAl2 and Cu4 Si are generated during the extrusion following the sintering.The mechanical properties of the alloy prepared are increased obviously,where the hardness,tensile strength and elongation reach 71.5 HV,400 MPa and 13.8%,respectively.The fracture morphology of the alloy prepared is changed from typical brittle fracture of rock candy to ductility fracture containing dimples.