Coherent interface strengthening of ultrahigh pressure heat-treated Mg-Li-Y alloys

Shun Zhang^1,2，Yong Sun¹，Ruizhi Wu²，Xiang Wang²，Xiao-Bo Chen³，Carlos Fernandez⁴，Qiuming Peng¹

1. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University2. Key Laboratory of Superlight Materials & Surface Technology, Ministry of Education, Harbin Engineering University3. School of Engineering, RMIT University4. School of Pharmacy and Life Sciences, Robert Gordon University

摘 要：Achieving good strength-ductility of Mg alloys has always been a crucial issue for the widespread applications of Mg-based structural materials.Herein,an unexpected double-stage strengthening phenomenon was discovered in Mg-8Li-1Y（wt.%） alloys through high pressure（6 GPa） heat treatments over a range of 700-1300℃.Attractively,the yield strength values are improved remarkably without losing their ductility.The low temperature strengthening mechanism is mainly driven by the formation of large-volume nanoscale contraction twins.In contrast,the high-temperature strengthening reason is ascribed to the presence of densely nano-sized stacking faults.Both coherent interfaces contribute effectively to high mechanical strength without any tradeoff in ductility.

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