Nanostructured Nb reinforced NiTi shape memory alloy composite with high strength and narrow hysteresis

An in-situ nanostructured Nb reinforced NiTi shape-memory alloy composite was fabricated by mechanical reduction of an as-cast Nb-NiTi eutectic alloy. The composite exhibits large elastic strain, high strength, narrow hysteresis, and high mechanical energy storage density and efficiency during tensile cycling. In situ synchrotron high-energy X-ray diffraction revealed that these superior properties were attributed to the strong coupling between nanostructured Nb and NiTi matrix during deformation. Furthermore, this study offers a good understanding of the deformation behavior of the nanoscale reinforcement embedded in the metal matrix deformed by stress-induced phase transformation. (C) 2013 AIP Publishing LLC.