Preparing method of memory alloy nano lamination Ni/Ti preformed blank

Abstract

The invention discloses a preparing method of a memory alloy nano lamination Ni / Ti preformed blank, and belongs to the technical field of functional composites. The method comprises the steps of firstly, material preparing, secondly, packaging and thirdly, rolling. Room temperature accumulative roll bonding is adopted, in combination with wrapping of a jacket, the deforming is limited and obstructed, Ni / Ti coordinative deforming is facilitated, and the problems that in the traditional smelting process, NiTi alloy easily introduces impurity elements, the material machining property is poor, inthe cold machining process, deforming resistance is large, and the pass deforming amount is small are solved. Due to the fact that three segments of accumulative roll bonding are carried out at the room temperature, the middle process is not annealed, the residual stress of the finally-composited Ni / Ti layered preformed blank is large, the activity between Ni atom and Ti atom interfaces is high, the layered Ni / Ti preformed blank is high in hardness, and the elastic modulus is high. Time needed by generating of the NiTi shape memory alloy through the certain-temperature reaction diffusion of Niand Ti is shorter, TiNi alloy grains can be generated through refining to a certain degree, the NiTi high-quality shape memory alloy is improved, the grains are thin, the phase change temperature stability can be improved, and the austenitization phase change temperature is slightly increased.

Description

technical field [0001] The invention belongs to the technical field of functional composite materials, in particular to a method for preparing a memory alloy nano-laminated Ni / Ti preform. Background technique [0002] NiTi shape memory alloy is a functional composite material, which is widely used in aerospace, biomedical, energy and chemical industries, etc. It not only has high specific strength, good wear resistance and corrosion resistance, high fatigue strength, but also has shape memory Effect (SME) and superelasticity (SE), as well as good biocompatibility and other advantages. At present, the commonly used method for preparing NiTi shape memory alloys is mainly to obtain NiTi alloy ingots by smelting, and then control the microstructure by subsequent hot or cold processing of the ingots, so that they have shape memory properties. However, the hot processing method in the prior art has harsh process conditions, and it is easy to cause surface and even internal oxidat...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problems of element pollution in the NiTi alloy ingot obtained by the traditional smelting method, large deformation resistance in the cold working process, small pass deformation, low material plasticity, and complicated process, the present invention provides a memory alloy nano-laminated Ni / Ti prefabricated The preparation method of the billet is to prepare the laminated Ni / Ti preform by using the three-stage cumulative rolling large plastic deformation technology, combined with the cold working method to refine the grains, increase the specific surface interface of titanium and nickel grains, and reduce the layer thickness. The distance between the layer and the layer, as the grain size decreases, the atomic activity is enhanced, and the titanium atoms and nickel atoms are fully reacted and diffused at a certain temperature and time, which promotes their rapid alloying

Images