Effect of double aging and microalloying on the age hardening behavior of a Mg–Sn–Zn alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 530; pp. 1 - 8
• Main Authors: Sasaki, T.T., Oh-ishi, K., Ohkubo, T., Hono, K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.12.2011; Elsevier
• Subjects: Age hardening; Cross-disciplinary physics: materials science; rheology; Dispersions; Double aging; Exact sciences and technology; Hardness; Magnesium base alloys; Materials science; Mg–Sn alloy; Microalloying; Nucleation; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precipitates; Precipitation; Solid solution, precipitation, and dispersion hardening; aging; Treatment of materials and its effects on microstructure and properties; Mg–Sn alloy; Microalloying; Precipitation; Double aging; Alloying elements; Magnesium base alloys; Transmission electron microscopy; Electron diffraction; Heterogeneous nucleation; Aging; Mg-Sn alloy; Solid solution hardening; Age hardening
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2010.05.010

► Age hardening response of Mg–Sn–Zn alloy is enhanced by double aging. ► Polygonal shaped Mg 2Sn phase heterogeneously nucleates at the tip of MgZn 2 phase. ► Alloying with Al, Cu, Ca + Ag + Zr further increases the peak hardness of Mg–Sn–Zn alloy. We have investigated the effect of double aging and microalloying on the age hardening behavior of a Mg–2.2Sn–0.5Zn alloy. The double aging at 473 K after pre-aging at 343 K lead to an increased peak hardness to more than 80 HV as a result of the refinement of the polygonal Mg 2Sn precipitates by the heterogeneous nucleation at densely dispersed MgZn 2 precipitates. The age hardening response of the Mg–2.2Sn–0.5Zn alloy was further enhanced by microalloying with 0.2Cu (at.%), 0.2Ca–0.2Ag–0.2Zr or 1.0Al. In particular, the peak hardness of the Mg–2.2Sn–0.5Zn–1.0Al alloy was 95 HV at 433 K, which was attributed to the synergy effect of the dispersion of the fine rod and polygonal Mg 2Sn precipitates and solution hardening with Al.