Stress-Rupture and Stress-Relaxation of Sic\Sic Composites at Intermediate Temperature

Real‐Time Monitoring of Thermal Cycling Damage in Ceramic Matrix Composites Under a Constant Stress

“…Fracture process and mechanics of the fiber‐reinforced CMCs during mechanical loading have been widely investigated by many previous researchers, mainly based on continuous AE monitoring of the loading procedure and qualitative or quantitative discussion of the raw data. The AE studies of damage evolutions and failure mechanisms in the CMCs have been experimentally conducted under monotonic tension, 4–6 hysteresis reloading/unloading, 7–9 stepwise incremental loading, 10 compression, 11 bending, 12,13 cyclic fatigue, 14–20 and even creep stress rupture both at room and elevated temperatures 21–23 . On the basis of data analysis of acoustic emission, interfacial mechanical parameters between fiber and matrix such as interfacial shear strength, interfacial debonding length, interfacial sliding stress, and partial debonding stress were investigated quantitatively by Morscher and colleagues 24–27 .…”

“…The AE studies of damage evolutions and failure mechanisms in the CMCs have been experimentally conducted under monotonic tension, [4][5][6] hysteresis reloading/unloading, [7][8][9] stepwise incremental loading, 10 compression, 11 bending, 12,13 cyclic fatigue, [14][15][16][17][18][19][20] and even creep stress rupture both at room and elevated temperatures. [21][22][23] On the basis of data analysis of acoustic emission, interfacial mechanical parameters between fiber and matrix such as interfacial shear strength, interfacial debonding length, interfacial sliding stress, and partial debonding stress were investigated quantitatively by Morscher and colleagues. [24][25][26][27] Kishi and Enoki, 28 and Yu et al 29 also successfully established a detection system of microcracks to estimate matrix cracking behavior in the CMCs.…”

High Temperature Si-Doped BN Interphases for Woven SiC/SiC Composites

“…In other words the Si -doped BN was exposed to the environment for -55 hours with little oxidation . For a composite containing conventional CVI BN, after 40 hours stress-rupture in air at 815°C (Figure 7), significant oxidation of the interphase had occurred and a thick glass layer had formed over 70% of the cross-section fusing fibers to one another, resulting in no fiber pull-out and composite embrittlement [12]. Tbis occurred even though the applied stress on the conventional BN composite was -65% of that of the Si-doped BN composite (see Figure 5).…”