粉末冶金法制备过共晶Al-23Si合金的微观组织与力学性能

Microstructure and mechanical properties of hypereutectic Al-23Si alloy fabricated by powder metallurgy

用Al-3Cu-1Mg-2Fe-23Si合金雾化粉末为原料,采用热压然后热挤压的方法制备Al-3Cu-1Mg-2Fe-23Si过共晶铝合金,利用金相显微镜、扫描电镜、万能电子拉伸机等研究该合金的显微组织与力学性能。结果表明:热压坯体中存在大量孔隙,相对密度为91%,抗拉强度为70 MPa,硬度为35HRB;经热挤压后相对密度达到99%,颗粒状硅相均匀弥散分布在基体中,硬度提高到72 HRB;进一步热处理后颗粒状硅相消失,合金硬度为84 HRB,抗拉强度达到219 MPa,断裂方式为脆性断裂。

The hypereutectic high-silicon aluminum alloy（Al-23Si） was fabricated by hot pressing and hot-extrusion process using Al-3Cu-1Mg-2Fe-23 Si alloy atomized powder as raw material. Optical microscopy, scanning electron microscopy, universal material testing machine were used to study the microstructure and mechanical properties of Al-23 Si alloy. Experimental results show that, there are still many holes exist after hot press process, and the tensile strength is 70 MPa. The density and hardness increase significantly after hot-extrusion process and the granular silicon appears and distributes in the matrix uniformly. The granular silicon phase disappears, the tensile strength reaches 219 MPa after heat treatment. The fracture mechanism is brittle fracture.