Study on brazing of TiNi shape memory alloy with stainless steels

• Published in: Journal of materials processing technology Vol. 176; no. 1; pp. 8 - 12
• Main Authors: Qiu, X.M., Li, M.G., Sun, D.Q., Liu, W.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 06.06.2006
• Subjects: Laser brazing; Microstructure; Stainless steel; Strength; TiNi shape memory alloy; TiNi shape memory alloy; Laser brazing; Microstructure; Stainless steel; Strength
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2005.06.004

TiNi shape memory alloy (TiNi SMA) and stainless steel (SS) were brazed by using silver-base filler metal with Ag 50–68 mass%, Cu 10–30 mass%, Zn 12–20 mass% and Sn 0–10 mass%. The results showed that properties and microstructures of the inhomogeneous joint depend on brazing heat input (laser output power and brazing time). Higher and lower heat inputs result in decreasing the joint strength due to low metallurgical bonding force between TiNi SMA and filler metal and structure coarsing in TiNi SMA heat affected zone. At proper brazing parameters, the joint strength can reach 320–360 MPa. The superelasticity loss of TiNi SMA heat affected zone increases with increasing brazing heat input, which is mainly attributed with structure coarsing and B19′ phase partly transforming into B2 phase in this zone. It is necessary to select proper brazing parameters for obtaining satisfactory joint properties.