DAMAGE SENSITIVITY AND ACOUSTIC EMISSION OF SIC/SIC COMPOSITE DURING TENSILE TEST AND STATIC FATIGUE AT INTERMEDIATE TEMPERATURE AFTER IMPACT DAMAGE
Résumé
This paper discusses the tensile resistance of an impact-damaged SiC/SiC based ceramic composite. As-received and impact-damaged specimens were subjected to static fatigue tests at 650 degrees C and 450 degrees C and to monotonous tensile tests at room temperature. Damage induced during the tensile and fatigue tests was characterized by the evolution of linear density of acoustic emission events (AE) during unloading-reloading cycles. Results of tensile tests at room temperature show the material impact insensitivity and the analysis of AE signals has demonstrated efficiency for proper investigation of damage evolution in the impacted specimens. During fatigue at 450 degrees C, 650 degrees C and under 80 MPa, both impact-damaged and as-fabricated samples survived 1000 hours. Residual strengths indicated insensitivity to impact damage. At 650 degrees C, damage evolution seemed to slow down from matrix self-healing.