Abstract
AbstractIn this paper, the temperature-dependent proportional limit stress (PLS) of SiC/SiC fiber-reinforced ceramic-matrix composites (CMCs) is investigated using the micromechanical approach. The PLS of SiC/SiC is predicted using an energy balance approach considering the effect of environment temperature. The relation between the environment temperature, PLS, and composite damage state is established. The effects of the fiber volume, interface properties, and matrix properties on the temperature-dependent PLS and composite damage state of SiC/SiC composite are analyzed. The experimental PLS and interface debonding length of 2D SiC/SiC composites with the PyC and BN interphase at elevated temperatures are predicted. The temperature-dependent PLS of SiC/SiC composite increases with the fiber volume, interface shear stress and interface debonding energy, and the matrix fracture energy and decreases with the interface frictional coefficient at the same temperature.
Highlights
Continuous SiC/SiC fiber-reinforced ceramic-matrix composites (CMCs) have excellent properties such as high specific strength, high specific modulus, wear resistance, oxidation resistance, corrosion resistance, radiation resistance, and insensitivity to cracks and noncatastrophic fracture, which make it a new type of thermalThe nonlinear stress–strain behavior of fiber-reinforced CMCs under tensile loading is mainly due to the internal damages of matrix cracking and the fiber/matrix interface debonding [12]
The micromatrix cracking first occurred in the matrixrich region due to the thermal residual stress which can be monitored using the acoustic emission or electrical resistance method that does not affect the linear behavior of fiber-reinforced CMCs
When the fiber volume is Vf = 35%, the proportional limit stress (PLS) decreases from σPLS = 130 MPa at an elevated temperature of T = 873 K to σPLS = 110 MPa at an elevated temperature of T = 1,273 K; and the fiber/matrix interface debonding length decreases from ld/rf = 4.6 at σPLS = 130 MPa to ld/rf = 3.9 at σPLS = 110 MPa
Summary
Continuous SiC/SiC fiber-reinforced ceramic-matrix composites (CMCs) have excellent properties such as high specific strength, high specific modulus, wear resistance, oxidation resistance, corrosion resistance, radiation resistance, and insensitivity to cracks and noncatastrophic fracture, which make it a new type of thermal. The nonlinear stress–strain behavior of fiber-reinforced CMCs under tensile loading is mainly due to the internal damages of matrix cracking and the fiber/matrix interface debonding [12]. The proportional limit stress (PLS) of fiber-reinforced CMCs corresponds to the first matrix cracking stress [13]. The macrotensile curves of fiber-reinforced CMCs can be divided into three stages: (1) the linear-elastic stage till the proportional limit stress, (2) the nonlinear stage of matrix cracking propagation and interface debonding stage till the saturation of the matrix cracking, and (3) the fibers failure stage after the saturation of matrix cracking [14,15,16,17]. The effects of the fiber volume, fiber/matrix interface properties, and matrix properties on the temperature-dependent PLS and composite internal damages are analyzed. The experimental PLS and fiber/matrix interface debonding length of 2D SiC/SiC composites with different interphase at elevated temperatures are predicted
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