A Prediction Method for Residual Tensile Strength of Ceramic Matrix Composites in Stress Oxidation Environment

Abstract

The invention discloses a method for predicting the residual tensile strength of a ceramic matrix composite material in a stress oxidation environment, which includes determining the variation law of the saturated crack distance of the SiC matrix of the unidirectional SiC / SiC composite material and the average distance of the cracks of the SiC matrix with stress; and determining the crack width of the SiC matrix The change law with stress and temperature; the oxygen concentration at different positions inside the material at different times can be obtained, and the interface consumption length, SiC fiber surface oxide layer thickness at the crack site change law with stress, temperature and time can be obtained; the SiC fiber axial Stress distribution; determine the size of oxidation defects on the surface of SiC fibers; deduce the expression of characteristic strength distribution of SiC fibers; deduce the expression of fracture probability of SiC fibers; obtain the maximum stress in bridging SiC fibers; solve the fracture of SiC fibers under certain temperature, stress and oxidation time Probability; obtaining the remaining strength of the material; the present invention accurately predicts the remaining tensile strength of the unidirectional SiC / SiC composite material at each moment, each temperature and tensile stress level.

Description

technical field [0001] The invention belongs to the technical field of material tensile strength prediction, in particular to a method for predicting the residual tensile strength of a ceramic matrix composite material in a stress oxidation environment. Background technique [0002] The high temperature resistance, low density and high [0003] Excellent properties such as specific strength and high specific modulus make it one of the irreplaceable new high-temperature structural materials in the aerospace field. It is widely used in aviation and aerospace engine hot-end parts, aerospace back-and-forth heat protection systems, high-speed brakes, and gas turbine hot-ends. components, high temperature gas filtration and heat exchangers, etc. [0004] Under service conditions, SiC / SiC materials need to withstand the joint action of stress and oxidation coupling. When the material is subjected to a certain tensile stress, cracks will appear in the SiC matrix, and the cracks wi...

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Problems solved by technology

[0008] The present invention aims at the deficiencies of the above-mentioned prior art, and provides a method for predicting the remaining tensile strength of the ceramic matrix composite material in a stress oxidation environment, so as to solve the problem in the prior art that the unidirectional SiC / SiC composite material cannot be accurately predicted in the stress oxidation environment. Ambient Residual Tensile Strength Issues

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