Tensile properties of duplex metal-coated SiC fiber and titanium alloy matrix composites

Effect of Cu/Ta duplex metal coating on interface characterization in SiC fibre-reinforced Ti-15 wt% V-3 wt% Cr-3 wt% AI-3 wt% Sn matrix composite

“…In both SiC/(Ti-15-3) and SiC/Cu/Ta/(Ti-l5-3), the critical interface debond strain energy release rate G: depends on the volume fraction p of the a phase in the matrix, that is GF increases with increase in p. This means that is controlled by the p -+ a transformation, which affects the axial residual compressive stresses in the fibres, because the interfacial mechanical properties are dependent on the state of these stresses in the fibres. In addition, in order to confirm this viewpoint further, some numerical data, which were reported in our previous work (Guo et al 1999), are shown in figure 12. These results show the dependence of the critical interface debond strain energy release rate on the volume fraction of a phase in the matrix.…”

“…These interfacial reactions lead to the formation of brittle carbide and silicide phases at the interface (Martineau et al 1984, Rhodes and Spurling 1991, Guo et al 1998a. Interface reaction layer cracking occurred at a lower applied stress level under either monotonic tensile or cyclic tensile loading conditions (Majumdar and Newaz 1992a,b, Majumdar et al 1993, Guo et al 1996a. The reaction layer cracking did not have significant influence on the monotonic tensile properties of the composite Newaz 1992a, Majumdar et al 1993), while it severely degraded the fatigue resistance of the composite under the cyclic loading condition Newaz 1992b, Guo et al 1996a,b).…”

“…The volume fraction p of c1 phase in the matrix near the interface region was measured by a quantitative image analysis method for both the SiC/(Ti-15-3) and SiC/Cu/Ta/ (Ti-15-3) before and after thermal exposure. The procedure from the measurement was the same as that reported elsewhere (Guo et al 1999). …”

Interface characterization of duplex metal-coated SiC fiber-reinforced Ti-15-3 matrix composites

“…It had been determined that this PVD process did not affect the strength of the SiC (SCS-6) fiber. [16,19] After the fabrication, the composites were treated by solutionzing at 1053 K for 0.5 hours, followed by an aging treatment at 723 K for 16 hours to stabilize the matrix structure. To investigate the effect of long-term thermal exposure on the interface reaction behavior, matrix microstructure, and interface mechanical properties, the composite panels were cut with a diamond saw into rectangular specimens 20-mm long, 15-mm wide, and 2-mm thick.…”

“…[14,15] The authors recently reported that the debonding of the SCS coating layer could be prevented by a duplex metal coating of Cu/Mo and Cu/W. [16] Thus, it is expected that the fatigue resistance of an unnotched composite is increased by the use of these duplex metal coatings. The characterizations of the interface reaction behavior of these composites and the effect of the duplex metal coatings on interface shear sliding stress have not yet been examined, however.…”