Microstructure refinement and fracture toughness enhancement of Nb-Si based alloy by CoAl2O4 refiner coupled with ultrasound treatmentShu Wang, Weipeng Xu, Xiong Chen, Dezhi Chen, Qi Wang and Ruirun ChenMATEC Web Conf., 401 (2024) 09002DOI: https://doi.org/10.1051/matecconf/202440109002