Rare Earth Element Yttrium Modified Mg-Al-Zn Alloy: Microstructure, Degradation Properties and Hardness

Long Liu; Fulai Yuan; Mingchun Zhao; Chengde Gao; Pei Feng; Youwen Yang; Sheng Yang; Cijun Shuai

doi:10.3390/ma10050477

Rare Earth Element Yttrium Modified Mg-Al-Zn Alloy: Microstructure, Degradation Properties and Hardness

Materials (Basel). 2017 Apr 28;10(5):477. doi: 10.3390/ma10050477.

Authors

Long Liu¹, Fulai Yuan², Mingchun Zhao³, Chengde Gao⁴, Pei Feng⁵, Youwen Yang⁶, Sheng Yang⁷, Cijun Shuai^{8

9}

Affiliations

¹ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. liulong@csu.edu.cn.
² Health Management Center, Xiangya Hospital, Central South University, Changsha 410008, China. yuanfulai2017@csu.edu.cn.
³ School of Material Science and Engineering, Central South University, Changsha 410083, China. mczhao@csu.edu.cn.
⁴ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. gaochengde@csu.edu.cn.
⁵ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. fengpei@csu.edu.cn.
⁶ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. yangyouwen@csu.edu.cn.
⁷ Human Reproduction Center, Shenzhen Hospital of Hongkong University, Shenzhen 518053, China. tobyys2000@aliyun.com.
⁸ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. shuai@csu.edu.cn.
⁹ Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha 410008, China. shuai@csu.edu.cn.

Abstract

The overly-fast degradation rates of magnesium-based alloys in the biological environment have limited their applications as biodegradable bone implants. In this study, rare earth element yttrium (Y) was introduced into AZ61 magnesium alloy (Mg-6Al-1Zn wt %) to control the degradation rate by laser rapid melting. The results showed that the degradation rate of AZ61 magnesium alloy was slowed down by adding Y. This was attributed to the reduction of Mg₁₇Al₁₂ phase and the formation of Al₂Y phase that has a more active potential, which decreased galvanic corrosion resulting from its coupling with the anodic matrix phase. Meanwhile, the hardness increased as Y contents increased due to the uniform distribution of the Al₂Y and Mg₁₇Al₁₂ phases. However, as the Y contents increased further, the formation of excessive Al₂Y phase resulted in the increasing of degradation rate and the decreasing of hardness due to its agglomeration.

Keywords: AZ61 magnesium alloy; degradation properties; hardness; microstructure.