Elevated temperature ablation mechanism and microstructural evolution of W-3Re-xHfC alloys in an oxy-acetylene torch environment.

Nozzle materials always withstand ultra-high temperatures (above 2000 °C) in space propulsion and other fields, which results in complex physical-chemical phenomena under actual operating conditions. The ablation mechanism and microstructural evolution of W-3Re-xHfC alloys were investigated to simulate the actual service conditions. Results show an outstanding ablation resistance. The linear ablation rate of the W 3Re matrix is 6.67 μm/s, the W-3Re-0.5HfC, W-3Re-5HfC and W-3Re-10HfC alloys are 2.93 μm/s, 2.23 μm/s and 2.26 μm/s, respectively. The linear ablation rates of W-3Re-0.5HfC, W-3Re-5HfC, and W-3Re-10HfC alloys decreased by 66%, 67%, and 67% compared with the W 3Re matrix, respectively. Thermochemical oxidation of the W 3Re matrix and HfC was the primary ablation mechanism of W-3Re-xHfC alloys. This work contributes to the design and improving the ablation resistance of W Re alloy applications in extreme environments. • Adding HfC particles significantly improves the ablation properties of W- 3Re alloy. • The ablation distance is shortened or the ablation time is prolonged, the worse ablation resistance • HfC and HfO 2 particles have high melting points, which nail the matrix grains and improve improving ablation resistance. • Thermochemical oxidation of the W- 3Re matrix and HfC particles is the primary ablation mechanism. [ABSTRACT FROM AUTHOR]