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In this paper, the tension-tension fatigue behavior of unidirectional SiC/Si 3 N 4 ceramic-matrix composite with strong and weak interface bonding at room temperature has been investigated using a micromechanical approach. The hysteresis loops models considering different interface slip cases have been developed to establish the relationships between fatigue hysteresis loops, hysteresis dissipated energy, hysteresis modulus, and the interface shear stress. The damage evolution process under tension-tension fatigue loading has been analyzed using hysteresis loops. By comparing experimental fatigue hysteresis dissipated energy with theoretical computational values, the interface shear stresses of SiC/Si 3 N 4 composite with weak and strong interface bonding were obtained for different cycle numbers. The fatigue life S‒N curves and broken fibers fraction versus cycle number curves corresponding to different fatigue peak stresses have been predicted. For SiC/Si 3 N 4 with strong interface bonding, the fatigue limit stress approaches to 75% tensile strength, which is much higher than that of composite with weak interface bonding, i.e., 58% tensile strength, due to the higher interface shear stress degradation rate for weak bonding interface. [ABSTRACT FROM AUTHOR]

Due to the wide bandgap of SiC, SiC-based photoelectric devices can be only driven by ultraviolet light, which essentially limit its application for a detection of visible and infrared light. In order to realize the non-UV operation of the SiC-based photoelectric devices applied in high temperature and high power regions, Ni/n-Si/N + -SiC heterostructure Schottky barrier photodiode has been studied. Energy-band structure of the Ni/n-Si/N + -6H-SiC structure was simulated by Silvaco-TCAD. And the non-UV photodiode with this structure was fabricated on 6H-SiC(0001) substrate. J-V measurements indicate that the device has good rectifying behavior with a rectification ratio up to 200 at 5V, and the turn-on voltage is about 0.7V. Under non-ultraviolet illumination of 0.6W/cm 2 , the device demonstrates significant photoelectric response with a photocurrent density of 2.9mA/cm 2 and an open-circuit voltage of 63.0mV. Non- ultraviolet operation of the SiC-based photoelectric device is initially realized. [ABSTRACT FROM AUTHOR]