Microstructure and properties of rheo-diecast Al-20Si-2Cu-1Ni-0.4Mg alloy with direct ultrasonic vibration process

来源期刊：中国有色金属学报(英文版)2010年第z3期

论文作者：吴树森 钟鼓 万里 安萍 毛有武

文章页码：763 - 767

Key words：semi-solid metals; rheocasting; Al-Si alloy; ultrasonic vibration; properties

Abstract: The microstructure and properties of Al-20Si-2Cu-1Ni-0.4Mg alloy fabricated with semi-solid rheo-diecasting process were studied. A newly developed direct ultrasonic vibration process (DUV process) was used in the preparation of the semi-solid slurry of this alloy. The results show that the primary Si particles in this alloy is about 20 μm in size under DUV for 90 s in the semi-solid temperature range, compared to about 30 μm in the alloy without DUV. It is discovered that the primary Si particles distribute more homogeneously and have regular shape, but have lower volume fraction after DUV. The tensile strength at room temperature is about 310 MPa, and the tensile strength and elongation of the semi-solid die castings are increased by 34% and 45%, respectively, compared with the traditional liquid die castings. The high-temperature tensile strength at 300 ℃ of this high Si aluminum alloy reaches 167 MPa, and the coefficient of thermal expansion is 17.37×10^-6/℃ between 25 and 300 ℃. This indicates that this high Si content Al-Si alloy produced with the DUV process is suitable to be used in the manufacture of pistons or other heat-resistant parts.

基金信息：the National Natural Science Foundation of China