中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 3 March 2016 |
（1. Key Laboratory of Automobile Materials, Ministry of Education,
Department of Materials Science and Engineering, Jilin University, Changchun 130025, China;
2. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences, Changchun 130022, China;
3. Key Laboratory of Advanced Structural Materials,
Ministry of Education, Changchun University of Technology, Changchun 130012, China）
Abstract:Mg-1Zn-0.5Ca alloys were prepared by traditional steel mould casting and water-cooled copper mould injection casting at higher cooling rate.Microstructure, mechanical properties and bio-corrosion resistance of two alloys were contrastively investigated. Grain size reduces remarkably and microstructure becomes homogenous when raising cooling rate. The bio-corrosion behaviour in 3.5% sodium chloride solution (3.5% NaCl) and Hank’s solution at 37°C was investigated using electrochemical polarization measurement and the results indicate that the alloy prepared at higher cooling rates has better corrosion resistance in both types of solution. Further mass loss immersion test in Hank’s solution reveals the same result. The reason of corrosion resistance improvement is that raising cooling rate brings about homogeneous microstructure, which leads to micro-galvanic corrosion alleviation. The tensile test results show that yield strength, ultimate tensile strength and elongation are improved by raising cooling rate and the improvement is mainly due to grain refinement.
Key words: Mg-1Zn-0.5Ca alloy; cooling rate; bio-corrosion resistance; micro-galvanic corrosion; mechanical properties
