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

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 mm) regardless of the Ce content, while the grain sizes of the two-stage annealed alloys increase obviously (-10.9 -11.9 mm). 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. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study systematically investigates the effect of minor Ce addition on the microstructure evolution and mechanical properties of rolled Mg-0.6Al-0.5Mn-0.2Ca alloy sheets. The Ce addition leads to changes in phase structure and improves the tensile strength. However, it also results in grain growth and abnormal grain growth.