Compression deformation behavior of silicide coating on Nb-Si based alloy

Abstract

The aim of this work is to investigate the compression deformation behavior of the Nb–Si based alloy with an Al–Y modified silicide coating at different conditions, including the height reduction, deformation temperature, strain rate and oxidation. The results showed that the silicide coating and substrate have a good coordinated deformation at a higher temperature or at a lower strain rate. While at a lower deformation temperature (1100 °C, 1200 °C) or a higher strain rate (0.005 s−1), the silicide coating shows a barrier effect on the deformation of substrate. At 1350 °C, the grains of NbSi2 phase in the coating were coarsened significantly. During the high temperature compression process, the coating can undergo a certain degree of plastic deformation, and NbSi2 phase in the coating would form sub-grain and a small amount of recrystallized grains. The crack initiation and propagation in the coating and substrate during compression deformation have also been discussed. The big cracks produced in the process of oxidation can be pressed gradually with the increase of the height reduction. The oxidation of the coating has no significant effect on the compressive properties of the alloy.