中國有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 27 No. 9 September 2017 |
（1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. Key Laboratory for Advanced Materials Processing of Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:A new and effective semisolid slurry preparation process with air-cooled stirring rod (ACSR) is reported, in which the compressed air is constantly injected into the inner cavity of a stirring rod to cool the melt. The slurry of a newly developed high thermal conductivity Al-8Si alloy was prepared, and thin-wall heat dissipation shells were produced by the ACSR process combined with a HPDC machine. The effects of the air flow on the morphology of α1-Al particles, mechanical properties and thermal conductivity of rheo-HPDC samples were studied. The results show that the excellent slurry of the alloy could be obtained with the air flow exceeding 3 L/s. Rheo-HPDC samples that were produced with the air flow of 5 L/s had the maximum UTS, YS, elongation, hardness and thermal conductivity of 261 MPa, 124 MPa, 4.9%, HV 99 and 153 W/(m·K), respectively. Rheo-HPDC samples show improved properties compared to those formed by HPDC, and the increasing rates of UTS, YS, elongation, hardness and thermal conductivity were 20%, 15%, 88%, 13% and 10%, respectively.
Key words: rheo-HPDC; Al-8Si alloy; air-cooled stirring rod; microstructure; mechanical properties; thermal conductivity
