中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 1 January 2016 |
（1. Department of Materials and Mechanical Engineering, Buein Zahra Technical University, Qazvin 3451745346, Iran;
2. Department of Mechanical Engineering, Faculty of Engineering, University of Ottawa,
Ottawa, 161 Louis Pasteur, KIN 6N5, Canada;
3. Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering,
Universiti Teknologi Malaysia (UTM), Johor Bahru 81310, Malaysia）
Abstract:The microstructure evolution, mechanical and corrosion properties of Al-11Si-2Cu-0.8Zn die cast alloy treated with Bi, Sb and Sr additions were investigated. The results of mechanical testing showed that all additions increased impact toughness, ultimate tensile strength, and elongation of the alloy as a result of change in eutectic Si morphology. The analysis of fracture surfaces revealed that with addition of Sr and to lesser extent Bi and Sb, the alloy exhibited a predominantly ductile fracture rather than quasi-cleavage brittle fracture. Moreover, with the additions of Sr, Bi and Sb, the quality index increased to 164.7 MPa, 156.3 MPa and 152.6 MPa respectively from 102 MPa for the base alloy. Polarization corrosion tests conducted in sodium chloride solution showed that the corrosion potential shifted to more negative values with additions of Sb, Bi and Sr, respectively. Corrosion immersion tests also revealed that the element additions have a detrimental effect on the corrosion rate of alloys, due to the increase of boundaries between the Al and eutectic Si phases.
Key words: aluminium die cast alloy; melt treatment; mechanical properties; fracture; corrosion
