Fabrication and properties of Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC high-entropy ceramic matrix composites via precursor infiltration and pyrolysis

摘要

In this work, Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC high-entropy ceramic matrix composites were reported for the first time. Based on the systematic study of the pyrolysis and solid-solution mechanisms of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C precursor by Fourier transform infrared spectroscopy, TG-MS and XRD, Cf/ (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC with uniform phase and element distribution were successfully fabricated by precursor infiltration and pyrolysis. The as-fabricated composites have a density and open porosity of 2.40 g/cm3 and 13.32 vol% respectively, with outstanding bending strength (322 MPa) and fracture toughness (8.24 MPa m1/2). The Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC composites also present excellent ablation resistant property at a heat flux density of 5 MW/m2, with linear and mass recession rates of 2.89 mu m/s and 2.60 mg/s respectively. The excellent combinations of mechanical and ablation resistant properties make the Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)CSiC composites a new generation of reliable ultra-high temperature materials.