Ultrahigh strength and high plasticity in TiAl intermetallics with bimodal grain structure and nanotwins

SCRIPTA MATERIALIA

卷:67

Article

Edalati, Kaveh^1,2  Toh, Shoichi³  Iwaoka, Hideaki¹  Watanabe, Masashi⁴  Horita, Zenji^1,2  Kashioka, Daisuke⁵  Kishida, Kyosuke⁵  Inui, Haruyuki⁵ 

[1] Kyushu Univ, Dept Mat Sci & Engn, Fac Engn, Fukuoka 8190395, Japan

[2] Kyushu Univ, WPI, Int Inst Carbon Neutral Energy Res WPI I2CNER, Fukuoka 8190395, Japan

[3] Kyushu Univ, Res Lab High Voltage Electron Microscopy, Fukuoka 8190395, Japan

[4] Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA

[5] Kyoto Univ, Dept Mat Sci & Engn, Fac Engn, Kyoto 6068501, Japan

关键词: Nanostructure;    High-pressure torsion (HPT);    Severe plastic deformation (SPD);    Stacking fault energy;    Ductility;   

DOI  :  10.1016/j.scriptamat.2012.07.030

来源: Elsevier

【 摘 要 】

Nanostructured intermetallics generally exhibit high strength but limited plasticity due to the covalent nature of their bonding. In this study, high-pressure torsion followed by annealing was used to produce TiAl intermetallics with two microstructural features: (i) bimodal microstructure composed of nanograins and submicrometer grains; and (ii) nanotwins. An exceptional performance, combining ultrahigh yield strength, similar to 2.9 GPa, and high strain to failure, similar to 14%, was achieved with micropillar compression tests. Twinning, dislocation slip and grain boundary sliding appear to be active under compressive stress. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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