Controlling Residual Stress in Metal Matrix Ceramic Fiber Composite

Abstract

In metal matrix composites the nature of the reinforcement can influence the development of residual stresses not only as a result of the mismatch in the thermal expansion coefficient between the fiber and the matrix but also caused by the interface of the materials during the processing cycles. The residual stress can be minimized through controlling the processing path and the thermal environment. We studied the residual stress formation and evolution in gamma titanium aluminide (Ti-47AL-2Ta) matrix. The matrix was reinforced with three different types of fibers: Alumina, Sapphikon, and Tiboride through hot isostatic pressing. The composite was heat treated for various combinations of time: 100, 200 and 500 hours; and temperature: 590°C, 815°C and 982 °C respectively. Residual stresses were measured in the gamma phase of the matrix using X-Ray diffraction.