Effect of Grain Size on Mechanical Properties of Mg-0.3at.%Y Dilute Alloy

Abstract:

In this study, a Mg-0.3at.%Y alloy was provided for a severe plastic deformation by high pressure torsion (HPT) and subsequent annealing. After the HPT by 5 rotations, nanocrystalline structures with a mean grain size of 0.23 μm having deformed characteristics were obtained. Fully recrystallized microstructures with mean grain sizes ranging from 0.66 μm to 32.7 μm were obtained by subsequent annealing at various temperatures. Room temperature tensile tests revealed that ultrafine grained (UFG; grain sizes smaller than 1 μm) specimen exhibited very high yield strength over 250 MPa but limited ductility. In contrast, good balance of strength and ductility was realized in fine grained specimens with grain sizes around 2~5 μm. Particularly, the yield strength and total tensile elongation of a specimen with a mean grain size of 2.13 μm were 184 MPa and 37.1%, respectively, which were much higher than those of pure Mg having a similar grain size. The significant effects of grain size and Y addition on the mechanical properties were discussed.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 790-795
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.790
• Online since: December 2018
• Authors: Rui Xiao Zheng*, Ichiro Kawarada, Wu Gong, Akinobu Shibata, Hidetoshi Somekawa, Shigenobu Ogata, Nobuhiro Tsuji
• Keywords: Ductility, High Pressure Torsion, Magnesium, Strength, Ultrafine Grains

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