A COMPARISON OF MECHANICAL RESPONSE OF MMC AT ROOM AND ELEVATED-TEMPERATURES

An investigation has been undertaken to determine the key deformation mechanisms for [0]8 and [90]8 Ti 15-3/SCS-6 laminae and [+/-45]2s and [0/90]2s laminates under monotonic loading at room temperature and at elevated temperature. The experimental results suggest that inelastic deformation in the [0]8 lamina is dominated by plastic deformation and that in the [90]8 lamina is dominated by both fiber/matrix debonding and plasticity. The [+/-45]2s laminate behavior is similar to the [90]8 lamina response in that a three-stage deformation behavior is observed as well. The [0/90]2s laminate also shows a characteristic two-stage deformation behavior. Elevated temperature response of the four layups were compared with their corresponding room temperature response. Results indicate that the characteristic deformation behavior for the laminae and the laminate remain similar under elevated temperature, although yield strength and other key mechanical properties are altered. At elevated temperature, matrix plasticity involved diffused and less planar slip compared with room temperature. Other than that, damage in the form of reaction zone cracks and fiber/matrix debonding (primarily for [90]8, [+/-45]2s and [0/90]2s layups) remained similar to those at room temperature.