Effect of micro-alloyed Ce on the microstructure evolution and mechanical properties of rolled Mg-0.6Al-0.5Mn-0.2Ca alloy sheets

• Published in: Journal of materials research and technology Vol. 19; pp. 3088 - 3099
• Main Authors: Li, Jia-Sheng, Li, Mei-Xuan, Hua, Zhen-Ming, Hu, Zhang-Ting, Wang, Hui-Yuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022; Elsevier
• Subjects: Age-hardening response; Heat treatment; Magnesium alloy; Mechanical property; Microstructure evolution; Heat treatment; Mechanical property; Age-hardening response; Microstructure evolution; Magnesium alloy
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2022.06.064

In this study, the effect of minor Ce addition (0, 0.1, and, 0.3 wt.%) on the microstructure evolution and mechanical properties of rolled Mg-0.6Al-0.5Mn-0.2Ca (AMX100) alloy sheets is systematically investigated under different annealing processes. With 0.1 wt.% Ce addition, partial Al8Mn5 phases turn into Al8Mn4Ce. With 0.3 wt.% Ce addition, the number of the Al8Mn4Ce further increases and the Al-Ce phases are observed. The single-stage annealed alloys exhibit similar uniform fine-grained structures (∼6 μm) regardless of the Ce content, while the grain sizes of the two-stage annealed alloys increase obviously (∼10.9-11.9 μm). Especially, the abnormal grain growth occurs in the two-stage annealed AMX100-0.3Ce alloy. After the aging treatment, the yield strength (YS) of the two-stage annealed alloys is increased by ∼25-45 MPa, which is greatly higher than that of the single-stage annealed alloys (∼1-8 MPa). Note that the two-stage annealed AMX100-0.1Ce alloy displays a significant age-hardening response with the ultimate tensile strength (UTS) of ∼272 MPa and the elongation to failure (EF) of ∼14%, which is attributed to the formation of Al and Ca enriched Guinier-Preston (G.P.) zones. This work sheds light on the design and fabrication of low-cost dilute magnesium alloys with admirable age-hardening ability.