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

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• 作者：Kaveh Edalati ; Shoichi Toh ; Hideaki Iwaoka ; Masashi Watanabe ; Zenji Horita ; Daisuke Kashioka ; Kyosuke Kishida ; Haruyuki Inui
• 关键词：Nanostructure ; High-pressure torsion (HPT) ; Severe plastic deformation (SPD) ; Stacking fault energy ; Ductility
• 刊名：Scripta Materialia
• 出版年：2012
• 出版时间：November, 2012
• 年：2012
• 卷：67
• 期：10
• 页码：814-817
• 全文大小：628 K

文摘

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, ¡«2.9 GPa, and high strain to failure, ¡«14 % , was achieved with micropillar compression tests. Twinning, dislocation slip and grain boundary sliding appear to be active under compressive stress.