Surface damage evolution during transient thermal shock of W-2%vol Y_2O_3 composite material in different surfaces

摘要

W-2%vol Y2O3 composite material were prepared by wet chemical and rolling methods. The thermal shock damage behaviors of rolling direction-transverse direction (RD-TD) and transverse direction-transverse direction (TD-ND) surfaces under one-pulse and 100-pulse thermal shock in different power densities were studied at room temperature. Results showed that the TD-ND surface was more resistant to transient thermal shock than the RD-TD surface. The RD-TD surface more likely to occur plastic deformation than the TD-ND surface, attributed to the gamma-fiber of RD-TD surface has a larger Schmid factor than a-fiber of TD-ND surface and is more prone to slip. The cracks generated and propagated more easily along the direction of grain elongation. With the increase in power density, transverse and longitudinal primary crack width, as well as surface roughness, first increased and then decreased. Under the transient thermal shock power density of 0.66 GW/m(2), the surface morphology of the material mainly manifested as primary and secondary cracks, without obvious plastic deformation. Moreover, the addition of Y2O3 particles is beneficial to resist crack propagation, but some Y2O3 particles exhibited a flake phenomenon due to multiple thermal shocks under high power density.