Microstructures and mechanical properties of Mg-10Ho-0.6Zr-xNd alloys
(1. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
2. Key Laboratory of Automobile Materials, Ministry of Education, Jilin University, Changchun 130025, China;
3. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences, Changchun 130022, China)
2. Key Laboratory of Automobile Materials, Ministry of Education, Jilin University, Changchun 130025, China;
3. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences, Changchun 130022, China)
Abstract: Mg-10Ho-0.6Zr-xNd (x=0, 1, 3 and 5, mass fraction, %) alloys were prepared by metal mould casting, and the microstructures and mechanical properties were investigated. The results show that the grain size of as-cast alloys reduces and the hardness and strength increase with the increase of Nd content. The alloys are aged followed by solid solution treatment. Mg-10Ho-0.6Zr-3Nd and Mg-10Ho-0.6Zr-5Nd alloys exhibit obvious age hardening response. The hardness value of Mg-10Ho-0.6Zr-5Nd alloy increases from HV104 at as-cast state to HV136 at peak-aged state. The maximum ultimate tensile strength and yield strength of the Mg-10Ho-0.6Zr-5Nd alloy are obtained in at peak-aged state, and the values are 323 MPa, 212 MPa at room temperature, and 258 MPa, 176 MPa at 250 ℃, respectively. The improvement of the tensile strength is mainly attributed to the fine and dispersively distributed plate-shaped β′ metastable phase.
Key words: Mg-Ho-Zr-Nd alloy; microstructure; age hardening behavior; mechanical properties