Microstructure and mechanical properties of continuous ceramic SiC and shape memory alloy NiTi hybrid fibers reinforced Ti-Al metal-intermetallic laminated composite.

An optimized continuous ceramic SiC and shape memory alloy NiTi hybrid fibers reinforced Ti-Al metal-intermetallic laminated composite (as-optimized CSMAFR-MIL) was designed and fabricated using vacuum hot pressing sintering technique. The microstructure characterization of the composite was performed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The formation mechanisms of the intermetallic layer were discussed. Furthermore, the mechanical properties of the as-optimized CSMAFR-MIL composite were measured via tensile tests. The experimental results indicated that the NiTi fibers were exhausted, and the inhomogeneous intermetallic layer was formed containing Al 3 Ni, Al 3 Ti, Al 3 Ti 0.8 V 0.2 intermetallics due to the reactions of Al with NiTi and Ti-6Al-4V alloy. Meanwhile, the intermetallic centerline, which usually appeared in Ti-Al laminated composite, was significantly eliminated in the as-optimized CSMAFR-MIL composite due to the diffusion reaction between NiTi fiber and Al. In addition, the SiC fibers combined well with the intermetallics, and the interfacial phases TiC and Al 4 C 3 were formed around the SiC fiber. Moreover, compared to continuous SiC fiber reinforced Ti-Al metal-intermetallic laminated (CFR-MIL) composite, the as-optimized CSMAFR-MIL composite possessed a good combination of high strength and superior ductility owing to the optimized microstructure of the composite and the mixed fracture mode of intermetallics. [ABSTRACT FROM AUTHOR]