Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (3): 405-416.DOI: 10.1007/s40195-022-01494-4

Previous Articles     Next Articles

Effects of Nb Addition on Charpy Impact Properties of TiVTa Refractory High-Entropy Alloy

Xue Yin1, Yan-Kun Dou1(), Xin-Fu He1(), Ke Jin2,3, Cheng-Long Wang1, Ya-Guang Dong2, Cun-Yong Wang2, Yun-Fei Xue2, Wen Yang1   

  1. 1Department of Reactor Engineering Technology Research, China Institute of Atomic Energy, Beijing 102413, China
    2School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
    3Advance Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China

Abstract:

In the present study, the effects of Nb addition on Charpy impact properties of TiVTa refractory high-entropy alloy with high strength-ductility trade-off were systematically studied by using the instrumented Charpy impact testing machine. The experimental results showed that the impact toughness was remarkably improved by Nb addition in TiVTa to form TiVTaNb alloy. The crack initiation energy and propagation energy of TiVTaNb were 67.3% and 24.9% higher than that of TiVTa, indicating that Nb addition simultaneously reinforced the resistance to crack initiation and propagation. The impact fracture of TiVTaNb exhibited larger bending degree of shear lips, deeper dimples and more secondary cracks which effectively dissipated more impact energy. The deformation mechanism of TiVTa alloy was dominated by dislocation activities. While in TiVTaNb, the deformation mechanism was synergized by dislocation activities and deformation twinning, which were the main contributors for the improved impact properties and the stronger crack resistance of TiVTaNb alloy under impact loading.

Key words: Refractory high-entropy alloys, Nb addition, Impact property, Crack resistance, Deformation mechanism