S. Mall,J.L Ryba Composites Science and Technology 68(2008)274-28 279 400c.02h(a 8. Fracture surface from stress rupture tests at lower magnification (100x):(a)400C steam, (b)750C steam, (c)950C steam (d)400C air,(e) eair,(f)950°air 50c1510he Ambient Air Conditions Fig 9. Fracture surface from stress rupture tests at intermediate magnification(1000x): (a)400C steam.(b)750C steam, (c)950C steam (d)400C air,(e)750°cair,()950°air.Fig. 8. Fracture surface from stress rupture tests at lower magnification (100·): (a) 400 C steam, (b) 750 C steam, (c) 950 C steam, (d) 400 C air, (e) 750 C air, (f) 950 C air. Fig. 9. Fracture surface from stress rupture tests at intermediate magnification (1000·): (a) 400 C steam, (b) 750 C steam, (c) 950 C steam, (d) 400 C air, (e) 750 C air, (f) 950 C air. S. Mall, J.L. Ryba / Composites Science and Technology 68 (2008) 274–282 279