Achieving ultra-high hardness of nanostructured Mg-8.2Gd-3.2Y-1.0Zn-0.4Zr alloy produced by a combination of high pressure torsion and ageing treatment

SCRIPTA MATERIALIA

卷:155

Article

Sun, W. T.¹  Qiao, X. G.¹  Zheng, M. Y.¹  Zhao, X. J.²  Chen, H. W.²  Gao, N.³  Starink, M. J.³ 

[1] Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China

[2] Chongqing Univ, Coll Mat Sci & Engn, Chongqing 400044, Peoples R China

[3] Univ Southampton, Fac Engn & Environm, Mat Res Grp, Southampton SO17 1BJ, Hants, England

关键词: Magnesium-rare earth alloy;    High pressure torsion;    Microstructure refinement;    Ageing response;    Solute segregation;   

DOI  :  10.1016/j.scriptamat.2018.06.009

来源: Elsevier

【 摘 要 】

A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt%) alloy is subjected to a series of thermal and mechanical treatments involving solution treatment, artificial ageing to peak hardness, high pressure torsion (HPT) and a second artificial ageing. During HPT precipitates dissolve and during the final post-HPT ageing, the supersaturated solid solution decomposes and solutes segregate at grain boundaries. By employing this T6 + HPT + T5 treatment, the hardness increases to 156 +/- 1 HV, which is much higher than that achieved by any other reported combination of thermal and thermo-mechanical processing of Mg alloys. The ultra-high hardness is due to the combined effects of solute segregation, grain refinement and high dislocation density. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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