等温锻造对碳化硅颗粒增强铝基复合材料断裂韧性的影响

Effect of Isothermal Forging on Fracture Toughness of SiC Particle Reinforced Aluminum Matrix Composite

开展了粉末冶金法制备的20%SiC_p/2009Al复合材料坯锭的等温锻造实验,通过金相观察、扫描电镜(SEM)、拉伸和断裂韧性测试等方法研究了不同变形量对锻件微观组织和力学性能的影响。结果表明,随着等温锻造变形量的增大,SiC颗粒分布更加均匀,锻件的强度和塑性显著提高。通过SEM对材料断裂韧性裂纹扩展路径观察发现,主裂纹扩展发生在SiC颗粒偏聚区域的铝基体中。复合材料的断裂方式为以基体韧性断裂和增强体脆性断裂这2种方式为主。

20%SiC_p/2009 Al composites fabricated by powder metallurgy（PM） method were processed by isothermal forging, and the effects of different deformation on microstructure and mechanical properties were studied by optical microscopy, scanning electronic microscopy（SEM）, tensile and fracture toughness testing. The results show that with the total strain increasing, distribution of SiC particles becomes uniform, the intensity and plasticity are significantly improved. The crack propagation paths of fracture toughness were observed by SEM. The main crack occurs in the aluminum matrix where SiC particles are agglomerated. The fracture mode of the composites combines toughness fracture of the matrix and particle brittle fracture.