Study on the Ultra-High Temperature Thermal Shock Resistance of a (Ta,Mo)Si2-ZrSi2-(Zr,Ta)C/TaSi2 Composite Coating on Ta10W
MATERIALS CHINA[ISSN:1674-3962/CN:61-1473/TG]
- Issue:
- 2026年08
- Page:
- 80-89
- Research Field:
- Publishing date:
Info
- Title:
- Study on the Ultra-High Temperature Thermal Shock Resistance of a (Ta,Mo)Si2-ZrSi2-(Zr,Ta)C/TaSi2 Composite Coating on Ta10W
- Author(s):
- YANG Jiaxiang; WANG Xin; LIU Yanming; WANG Zihao; GAO Xiang; YAN Peng
- 1.School of Material Science and Engineering, Xi’an Shiyou University, Xi’an 710065, China
2.Northwest Institute for Nonferrous Metal Research, Xi’an 710016,China
- Keywords:
- Ta-based alloy; silicide coating; ultra-high-temperature thermal shock; crystal-glass composite oxide film; failure mechanism; finite element simulation
- CLC:
- PACS:
- -
- DOI:
- -
- DocumentCode:
- Abstract:
- Tantalum alloys are promising candidate materials for hot-end components of hypersonic vehicles; however, their insufficient oxidation resistance and thermal shock stability under ultra-high-temperature thermal shock conditions remain critical challenges. In this study, a (Ta,Mo)Si2-ZrSi2-(Zr,Ta)C/TaSi2 composite coating was in situ prepared on a Ta10W alloy by slurry spraying followed by vacuum reaction sintering, and its damage behavior and failure mechanism under cyclic thermal shock from room temperature to 1600°C and 1700°C were investigated. The as-prepared coating consisted of an outer (Ta,Mo)Si2-ZrSi2-(Zr,Ta)C composite ceramic layer, a TaSi2 inner layer, and a Ta5Si3 coating/substrate interfacial reaction layer. After thermal shock, an “island-sea” crystal-glass composite oxide film was formed on the coating surface, mainly composed of a SiO2 glass phase with dispersed ZrO2/Ta2O5 crystalline oxide particles and residual silicide particles. The tested region of the coating remained overall continuous after 90 cycles from room temperature to 1600°C and 75 cycles from room temperature to 1700°C. With increasing thermal shock temperature and cycle number, vertical cracks inside the coating and inward oxygen diffusion along these cracks became more pronounced. Compared with thermal shock from room temperature to 1600°C, the coating subjected to thermal shock from room temperature to 1700°C exhibited similar oxidation products, but more severe degradation of residual silicides and the TaSi2 inner layer, accompanied by intensified local crack propagation and oxidation damage. Thermal-structural coupled finite element simulations revealed that crack edges and crack tips were the main stress concentration regions during cyclic thermal shock. The high tensile stress at crack edges promoted crack opening and propagation, providing short-circuit pathways for inward oxygen diffusion. Therefore, the thermal shock failure of the composite coating was mainly governed by defect accumulation in the oxide layer, crack propagation, inward oxygen diffusion along defects, and thermal stress concentration, rather than by overall spallation of the oxide film.
Last Update: 2026-06-30