Download or read book Environmental Effects on the Isothermal and Thermomechanical Fatigue of SCS-6/TIMETAL 21S Unidirectional Composites written by T. Nicholas and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of environment on the fatigue behavior of SCS-6/TIMETAL 21S [0]4composites is examined through a comparison of fatigue lives and damage progression for tests performed in air and high-purity helium. Isothermal and thermomechanical tests were conducted at 650°C and 150 to 650°C, respectively. Out-of-phase thermomechanical fatigue (TMF) lives of specimens tested in the inert environment show a x2 increase in life. In-phase TMF lives in inert and air environments, which are governed primarily by fiber bundle strength and matrix stress relaxation, are comparable.