Microstructure and Tensile Behavior of Ti-Rich Ti-Ni-Cu Melt-Spun Ribbon

Abstract

Microstructure and mechanical properties of Ti 51.5 Ni 25 Cu 23.5 ribbon fabricated by melt spinning were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and tensile tests. Some B19 martensite crystalline with (011) compound twin was embedded in the mainly amorphous ribbon, while the ribbon annealed at 450°C for 1 h is at fully martensitic state. Annealing process alter the preferential orientation from (022)-B19 to (111)-B19. Tensile fracture stresses of as-spun ribbon and the annealed ribbon are 1257 MPa and 250 MPa, respectively. The tensile fracture morphology of as-spun ribbon shows typical vein fringe while that of the annealed ribbon reveals fine but depth-inhomogeneous dimples. After tensile deformation, the annealed ribbon exhibits typical martensitic detwinning behavior accompanying with the strain contrast.