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

摘要

AbstractAn 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 Al3Ni, Al3Ti, Al3Ti0.8V0.2intermetallics 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 Al4C3were 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.Graphical abstractDisplay OmittedHighlights?An optimized hybrid fibers reinforced Ti-Al laminated composite is synthesized.?The mechanisms to eliminate the centerline in intermetallic layer are analyzed.?Each phase of the unique laminated composite is determined.?The as-optimized composite shows good comprehensive mechanical properties.]]>