Research progress in directional solidification of Nb-Si based high temperature alloys

Nb-Si based high temperature alloys possess higher melting points, relatively lower densities and attractive high temperature strength compared with Ni based superalloys. Therefore, they are expected to be promising candidate materials used at high temperatures beyond the maximum operating temperature of the Ni based superalloys. Directional solidification could improve both the room temperature ductility and high temperature strength of Nb-Si based high temperature alloys. Up to now, the directional solidification of Nb-Si based high temperature alloys has been conducted by cold crucible Czochralski method, floating zone melting techniques and integrally directional solidification process. In this paper, a review of directional solidification for Nb-Si based high temperature alloys is present, and the prospective research effort about directional solidification is also put forward.