Preparation and mechanical properties of ultra-high strength superalloy fibers

GH4169 superalloy fibers with ultra-high strength and ultra-fine grain (UFG) were fabricated by cold deformation and low temperature annealing, which provides a simple and effective method for preparation of UFG materials. In this study, the fibers were cold-drawn for 13 times and then cold-rolled 25 passes. Finally the annealing experiment is carried out on the cold-rolled samples. The fiber area was reduced by 97% and the grain size reaches 66 nm after cold deformation. In the subsequent annealing 450 ℃ for 30 min, the grain size was further reduced to 42 nm and the tensile strength of the fiber increases to about 2.05 GPa. The increase of the superalloy fiber energy storage and decrease of the curvature of the grain boundary lead to the low-temperature phase transformation. By controlling the annealing condition, these precipitation nanoparticles keep stable, the superalloy fibers are further refined and thus obtain higher strengthening superalloy fibers. [Display omitted] •The grain orientation is changed from random to and textures during cold drawing.•The combination of cold deformation and low-temperature annealing can induce the phase transformation in superalloy fiber.•The superalloy strength increased to 1.5 GPa and the fiber strength exceeds 2 GPa after heat treatment at 450 °C for 30 min.•The increase in fiber strength is caused by the increase of dislocations, texture, grain boundaries and precipitating phase.•A large amount of deformation will produce very fine strip-shaped grains with small dislocation and grain boundary angles.