The compressive creep behaviors were systematically studied on a pure Mg (0Y alloy) and various Mg-Y binary alloys (0.15Y, 1.5Y, 4.5Y, 7.5Y and 10.5Y alloys) at 523 K under various applied stresses. The loading directions were carried out parallel to rolling direction (RD), transverse direction (TD) and normal direction (ND), respectively. It was shown that the creep behaviors exhibited obvious dependence on loading direction in 0Y, 0.15Y, 1.5Y and 4.5Y alloys. The creep resistance had a sequence of ND > TD ≥ RD in these alloys. Their creep anisotropy was caused by cross-slip and twinning dominating the creep along RD and TD while dislocation climb and pyramidal <c+a> slip prevailing along ND. Compared to 0Y, 0.15Y and 1.5Y alloys, the more random basal texture weakened cross-slip and twinning along RD and TD and aroused cross-slip along ND, resulting in the decreased creep anisotropy in 4.5Y alloy. Inversely, 7.5Y and 10.5Y alloys showed a nearly creep isotropy due to cross-slip and pyramidal <c+a> slip dominated the creep along all three loading directions. Moreover, compared to 0Y alloy, the creep resistance was found to be slightly increased in 0.15Y alloy and significantly increased with increasing Y content above 1.5wt%. It was attributed to that solution strengthening and pyramidal <c+a> dislocations collaboratively increased the creep resistance. The improved hindering effect on twinning was also helpful to increase the creep resistance along RD and TD. Besides, dynamic precipitation strengthening assisted the increment of creep resistance in 10.5Y alloy. Thus, the addition of concentrated Y element in Mg alloys is a valid solution to eliminate the compressive creep anisotropy and simultaneously enhance the creep resistance.

Keywords: Magnesium alloy; Mechanical behavior; Microstructure; Deformation mechanism; Heat treatment.

Qinghuan Huo, born in 1989, is an associate professor in School of Materials Science and Engineering, Central South University, China.

The major research fields are microstructure characterization, plastic processing, mechanical behaviors of light metals such as Mg alloys and Al alloys. To date, projects including National Natural Science Foundation of China and Natural Science Foundation of Hunan Province have been carried out. Over 40 academic papers (First Author and Corresponding Author) have been published in the journals ranking in JCR Q1, and 16 Chinese patents (First Inventor) have been authorized.

The work experience is here:

03/2018 – Present: Central South University, China

Major: Materials Science and Engineering

Position: Associate Professor

10/2017 – 03/2018: Tohoku University, Japan

Major: Materials Science

Position: Researcher

The education experience is here:

10/2014 – 09/2017: Tohoku University, Japan

Major: Materials Science

Degree: Doctor of Engineering

09/2011 – 12/2013: Central South University, China

Major: Materials Science and Engineering

Degree: Master of Engineering

09/2007 – 06/2011: Central South University, China

Major: Materials Science and Engineering

Degree: Bachelor of Engineering