快速凝固喷射沉积制备Al-40Si组织分析

Microstructure analysis of rapidly solidified Al-40Si alloy fabricated by spray deposition

针对应用广泛的低密度、低膨胀、高热导、高比强的高硅铝合金,采用快速凝固喷射沉积技术制备了Al-40Si高硅铝合金锭坯,通过光学显微镜及扫描电镜对其组织进行了分析.结果表明：合金组织特征为初生Si相均匀弥散分布于α-Al基体中,未出现共晶Si组织;随着合金中Si含量的增加,初生硅相的数量增加,平均尺寸增大;本试验所制备的Al-40Si合金中初晶硅粒子大小为5～30μm,并随合金锭坯部位的不同,初生Si大小不同,中心部位最小,底部次之,边部最大.

High-silicon aluminum alloy is a widely applied material possessing low density, low thermal expansion coefficient, high thermal conductivity and tensile strength. In this experiment, Al-40Si high-silicon aluminum alloy ingot was fabricated by rapid solidification/spray deposition, microstructure was analyzed through SEM and optical microscopy. Experimental results indicated that primary silicon particles are uniformly distributed in α-Al matrix , without eutectic silicon existing; primary Si particles increase in quantity and size with the increasing Si content; its size range is about 5 - 3μm in Al-40Si ingot, and particle size varies with different part of the ingot, at the center, it is the smallest, it is medium at the bottom and at the side, the largest.