High-temperature slow crack growth of SiC–Mo5(Si,Al)3C composites determined by constant-stress-rate testing

A novel SiC–Mo5(Si,Al)3C composite was fabricated through a melt-infiltration process, and the slow-crack-growth (SCG) behavior of the composite was characterized over four stressing rates ranging from 0.01 to 20 MPa/s both at 1200 and 1300°C in 1 atm argon, using the constant-stress-rate (“dynamic fatigue”) test. The composite shows a high resistance to the SCG at 1200°C, where the slow-crack-growth parameter n was determined to be 86. At 1300°C, however, no significant SCG behavior was observed for n higher than 500.