Fatigue Damage and Lifetime of SiC/SiC Ceramic-Matrix Composite under Cyclic Loading at Elevated Temperatures

Area of Science:

• Materials Science
• Mechanical Engineering
• Ceramic Matrix Composites

Background:

• 2D SiC/SiC composites are advanced materials for high-temperature applications.
• Understanding their fatigue behavior under cyclic loading is crucial for structural integrity.

Purpose of the Study:

• To investigate the fatigue damage and lifetime of 2D SiC/SiC composites.
• To analyze the effect of air and steam environments on fatigue properties at various temperatures (750-1300 °C).

Main Methods:

• Cyclic fatigue loading experiments were conducted.
• Damage evolution was analyzed using fatigue hysteresis dissipated energy, modulus, peak strain, and interface shear stress.
• Fatigue life stress-cycle (S-N) curves and fatigue limit stresses were predicted.

Main Results:

• Steam accelerated damage development in SiC/SiC composites.
• Steam increased the rate of fatigue hysteresis dissipated energy and peak strain.
• Steam decreased the rate of fatigue hysteresis modulus and interface shear stress.
• Fatigue limit stresses were significantly reduced in steam compared to air across all tested temperatures.

Conclusions:

• The presence of steam significantly degrades the fatigue performance of 2D SiC/SiC composites.
• Fatigue life and limit stresses are temperature-dependent and are more pronouncedly reduced by steam at higher temperatures.