Abstract
Nb-Si-based alloys show great potential to sur-pass the widely used Ni-based superalloys.The element Sr is widely applied in aluminum and magnesium alloys,but reports about the effects of Sr on Nb-Si-based alloys are quite rare.So,Nb-Si-based alloys with nominal composi-tions of Nb-15Si-24Ti-4Cr-2Al-2Hf-0/0.05/0.15Sr(at％)were prepared by directional solidification and heat treat-ment.The microstructural characterization and room tem-perature fracture toughness of Nb-Si-based alloy were systematically investigated.Results show that all these alloys consist of Nb5Si3 phase embedded within Nb solid solution(Nbss)matrix.The Nb5Si3 phase becomes refined and more discontinuous after adding minor Sr.As for the fracture toughness,0.05 at％and 0.15 at％Sr additions do not cause significant change.The discontinuous and refin-ing mechanism of Sr element was studied,and the analysis of toughness decreasing with Sr addition reveals that the size of Nbss phase plays a crucial role in determining the fracture toughness.
基金项目
National Natural Science Foundation of China(51471013)
National Natural Science Foundation of China(51571004)
National Natural Science Foundation of China(51401017)
维普
万方数据