(1. 西南交通大学 材料科学与工程学院，成都 610031；
2. 华中科技大学 材料成形与模具技术国家重点实验室，武汉 430074)
摘 要: 将采用超声振动制备的过共晶Al-Si合金A390浆料在不同温度下进行流变压铸成形，研究浆料浇注温度对过共晶Al-Si合金流变压铸试样组织和力学性能的影响。结果表明：过共晶Al-Si合金A390流变压铸试样组织中初生Si主要由浆料制备过程中形成的大块Si(Si1)和在压铸模型腔中形成的细小Si(Si3)组成；在580~640 ℃范围内，随着浆料浇注温度升高，Si1平均尺寸先减小后增大，而Si3尺寸稳定在7~15 μm之间。过共晶Al-Si合金A390半固态浆料的适宜浇注温度范围为600~620 ℃，在此范围内可以得到抗拉强度超过260 MPa的A390合金流变压铸试样。
关键字: Al-Si合金；半固态浆料；流变压铸；过共晶；力学性能
（1. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
2. State Key Laboratory of Materials Processing and Die & Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:The hypereutectic Al-Si alloy A390 slurry was prepared by ultrasonic vibration and rheo-diecasted at different temperatures, and the effect of slurry pouring temperature on the microstructure and mechanical properties of hypereutectic Al-Si alloy rheo-diecasting sample was investigated. The results show that, the primary Si in the microstructure of rheo-diecasting sample of A390 alloy is mainly composed of large Si (Si1) formed during slurry preparation process and small Si (Si3) formed in die cavity; with the slurry pouring temperature increasing from 580 to 640 ℃, the average size of Si1 first decreases and then increases while that of Si3 maintains in the range of 7−15 μm. It is also found that the slurry pouring temperature suitable for rheo-diecasting of hypereutectic Al-Si alloy A390 semi-solid slurry is 600−620 ℃, and in this range the tensile strength of rheo-diecasting sample is up to more than 260 MPa.
Key words: Al-Si alloy; semisolid slurry; rheo-diecasting; hypereutectic; mechanical properties
