Mechanical properties and structural stability of a bulk nanostructured metastable aluminum-magnesium system

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:796

Article

Han, Jae-Kyung¹  Liss, Klaus-Dieter^2,3,4  Langdon, Terence G.⁵  Jang, Jae-il⁶  Kawasaki, Megumi¹ 

[1] Oregon State Univ, Sch Mech Ind & Mfg Engn, Corvallis, OR 97331 USA

[2] Guangdong Technion Israel Inst Technol, Mat & Engn Sci Program, Shantou 515063, Guangdong, Peoples R China

[3] Technion Israel Inst Technol, IL-32000 Haifa, Israel

[4] Univ Wollongong, Sch Mech Mat Mechatron & Biomed Engn, Wollongong, NSW 2522, Australia

[5] Univ Southampton, Dept Mech Engn, Mat Res Grp, Southampton SO17 1BJ, Hants, England

[6] Hanyang Univ, Div Mat Sci & Engn, Seoul 04763, South Korea

关键词: Grain refinement;    High-pressure torsion;    Metastable phase;    Plasticity;    X-ray diffraction;   

DOI  :  10.1016/j.msea.2020.140050

来源: Elsevier

【 摘 要 】

The mechanical properties and structural stability of a high-pressure torsion (HPT)-induced bulk nanostructured metastable Al-Mg system were examined after natural aging at room temperature for 60 days. The sample demonstrated a high yield strength of 1.3-1.5 GPa with an excellent plasticity by achieving a high strain rate sensitivity of 0.036. The high hardness is attributed to the concurrent contributions of grain refinement and solid solution strengthening. An X-ray diffraction analysis revealed a high compositional microstrain of similar to 0.0202 due to the supersaturation of Mg in the Al matrix after processing. This microstrain increased to similar to 0.0274 after natural aging due to the heterogeneous distribution of supersaturated Mg solutes without any nucleation of a second phase, thereby demonstrating a reasonable structural stability.

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