Creep Behavior of a Unidirectional SCS-6/Ti-15-3 Metal Matrix Composite at 450°C

As the first step to understand the creep behavior of a unidirectional SCS-6/Ti-15-3 metal matrix composite, creep tests were performed at 450°C using specimens reinforced with fibers oriented at 0 deg (longitudinal), 45 deg (off-axis), and 90 deg (transverse) to the specimen axis. Measuring the elongation in the gage section, we found that creep deformation and rupture can occur even in the longitudinal creep at stress levels much lower than the tensile strength although the SCS-6 fiber itself does not creep at all, and that the 45 deg off-axis creep has some ductility, which is greater at lower stress, whereas the transverse creep behavior is relatively brittle. Results of the longitudinal creep tests were discussed on the basis of the relaxation of stress in the matrix as well as the bundle strength of fibers.