Low temperature joining of NiTi shape memory alloy with Au-Si isothermal solidification

Abstract Owing to the isothermal solidification of eutectic Au-Si filler, NiTi joint that could endure 700 °C has been successfully manufactured at 430 °C for the first time. The joining temperauture is within the aging temperature range, which is harmless to the properties of the NiTi base metal. A total consumption of the eutectic Si leaves a seam full of Au, whiskers and nanocrystalline layers due to the reaction of Si and NiTi. With the high-density stacking faults, the nanocrystalline layers at the interface exhibits ultra-high mechanical property, which strengthen the interfaces.