SiC颗粒增强铝基复合材料的显微组织与力学性能

Microstructure and Mechanical Properties of High Volume Fraction SiC_p Reinforced Heat Resistant Aluminum Matrix Composites

采用压铸浸渗法制备了体积分数为50%的SiC/Al-5·3Cu-0·8Mg-0·6Ag-0·5Mn耐热铝基复合材料。通过拉伸测试与组织观察,研究了高体积分数SiC颗粒增强对基体合金的显微组织与力学性能影响。结果表明,在基体Al-5·3Cu-0·8Mg-0·6Ag-0·5Mn合金中掺入高体积分数的SiC颗粒后,复合材料的时效硬化与拉伸性能得到了大幅度的提高,185℃峰时效处理后的抗拉强度从356MPa增大到520MPa。SiC/Al-5.3Cu-0.8Mg-0.6Ag-0.5Mn复合材料的组织致密,分布均匀,其断裂方式包括界面脱开、基体韧断和增强体开裂。高体积分数SiC颗粒的增强并不改变基体合金的时效析出过程,析出相由Ω相和少量θ′相组成,但SiC颗粒与基体之间发生了界面反应,生成了纳米级的Al4C3化合物。

SiC/Al-5.3Cu-0.8Mg-0.6Al-0.5Mn heat resistant aluminum matrix composites with volume fraction of 50% SiC were prepared by squeezing-infiltration method.The effects of high volume fraction SiC particle on the microstructure and mechanical properties of the alloy have been investigated.The results show that high volume fraction SiC particle can greatly improve the aging hardening and tensile strength of the composites,where the tensile strength of the composites can be increased from 356 MPa to 520 MPa with peaking aging at 185 ℃.The SiC/Al-5.3Cu-0.8Mg-0.6Al-0.5Mn heat resistant aluminum matrix composites possesses a compact and uniformly distributed microstructure,and its fracture mode is characterized by the boundary separation,toughness fracture of the matrix and particle crack.Although the high volume fraction SiC particle can not affect the aging precipitation process of the matrix alloy,in which the precipitate is composed of Ω phase and minor θ' phase,the interfacial reaction between SiC particle and matrix alloy can be observed to create nano-scale Al4C3 phase.