Influences of annealing on mechanical properties and shape memory effects of laser welding joints of Ni47Ti44Nb9 alloy

Abstract:

In order to reduce the manufacturing cost of fastening rings made of NiTiNb wide hysteresis memory alloy, the Influences of annealing on mechanical properties and shape memory effects of laser welding joints were investigated. The welding were annealed at 850 ℃. The results showed that the microstructure of the welding joints was coarse and uneven. The Tensile strength and elongation of the joints were significantly lower than that of the base metal. After annealing, recrystallization leads to more uniform microstructure of welding joints. The tensile strength of base metal and welding joints decreased substantially, but the elongation increased greatly. The elongation of welding joints has increased to 28.57%. After 13% bending deformation at -40 ℃, the shape recovery rate of the annealed welding joints was closed to that of the matrix.