关键词: TiNi形状记忆合金, 不锈钢, 钎焊, 性能, 组织

Abstract: TiNi shape memory alloy(TiNi SMA) is brazed to stainless steel(SS) by using silver-based filler metal with Ag 50%～68%, Cu 10%～30%, Zn 12%～20% and Sn 0%～10% and by means of laser welder. The microstructures and properties of brazing joint are studied by means of adjusting technological parameters(laser output power and brazing time). The results showed that the AgCuZnSn filler metal is good for the wettability to brazing TiNi SMA and SS. Joint interface be-tween filler metal and TiNi SMA is smooth and compact. A reaction layer is formed between filler metal and SS. There are important influences of brazing technological parameters on the microstructures and properties of TiNi SMA heat affected zone. The higher effective heat input will result in grain growth, hardness reducing and plasticity increasing in the heat affected zone of TiNi SMA. The high joint tensile strength, shape memory effect and superelasticity could be obtained by strictly controlling brazing technological parameters.

Key words: Brazing, Microstructures, Properties, Stainless steel, TiNi shape memory alloy