Thermal Shock Behavior and Mechanism of Ta/Ta0.5Hf0.5C Laminated Composite Under Plasma Flame
Ta/Ta0.5Hf0.5C laminated composite shows great potential to be used as wing leading edges and nose caps due to its good mechanical properties and ablation resistance.However,the thermal shock behavior of the composite is rarely reported,as such,it is hard to evaluate whether the composite can serve as a structural material stably.The plasma flame and finite element method(FEM)were employed to investigate the thermal shock behavior of Ta/Ta0.5Hf0.5C laminated composite.By analyzing the morphologies and microstructure of the tested sample,it is found that Ta/Ta0.5Hf0.5C laminated composite possesses great thermal shock resistance since no cracks are observed on the internal and external surfaces of the composites after 120 cycles of plasma flame pulse assessment.Based on the measured temperature during thermal shock testing,the thermal stress distribution field inside the testing sample was built successfully.Result reveals that the maximum thermal stress(207 MPa)caused by plasma flame occurs at the moment of cooling.After 120 cycles of stress cycling,the retention rates of strength and toughness of the composites are 70.1％and 73.9％,respectively.High strength and excellent crack propagation resistance are the main reasons for the excellent thermal shock resistance of Ta/Ta0.5Hf0.5C laminated composite.
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