Method for improving function stability of nickel-titanium shape memory alloy

Abstract

The invention relates to a method for improving the function stability of a nickel-titanium shape memory alloy, and belongs to the field of nickel-titanium shape memory alloys. According to the method, dislocations and other defects are introduced into the nickel-titanium shape memory alloy, the dislocations serve as activity position points for promoting second phase nucleation, then, fine and evenly-distributed nano reinforcement phases are formed in a matrix structure of the nickel-titanium shape memory alloy through later aging treatment, accordingly, the matrix strength of the nickel-titanium shape memory alloy is obviously improved, and then the function stability of the alloy is improved. Meanwhile, in the method, only temperature martensite phase change induction circulation or stress martensite phase change induction circulation need to be conducted on a nickel-titanium shape memory alloy component before aging treatment, and operation is simple and convenient; and the methoddoes not have the requirement for the shape of the nickel-titanium shape memory alloy component, and the method is adaptive to the complex nickel-titanium shape memory alloy component and capable of effectively improving the function stability of the complex nickel-titanium shape memory alloy component.

Description

technical field [0001] The invention belongs to the field of nickel-titanium shape memory alloys, and in particular relates to a method for improving the functional stability of nickel-titanium shape memory alloys through the synergistic effect of cyclic loading and low-temperature aging. Background technique [0002] Nickel-titanium shape memory alloy exhibits shape memory effect and superelasticity, and is an intelligent material integrating sensing and driving. It has broad application prospects in the automotive industry, artificial intelligence, aerospace, marine transportation, and biomedical fields. Nickel-titanium shape memory alloy components generally undergo repeated phase transformation processes in practical applications. In this process, the accumulation of plastic deformation caused by cyclic phase transformation is the main reason for the decrease in the functional stability of nickel-titanium shape memory alloy components. . This severely limits the servic...

AI Technical Summary

Problems solved by technology

At present, the use of severe plastic deformation and post-treatment to refine the structure of nickel-titanium shape memory alloy mainly has the following disadvantages: (1) Due to the characteristics of high strength and strong work hardening ability of nickel-titanium shape memory alloy, it needs to be processed at a higher temperature. Severe plastic deformation process, which will seriously limit the effect of grain refinement, and it is difficult to obtain a grain structure below 100nm; (2) The severe plastic deformation process is only suitable for samples with simple shapes (such as plates, rods, pipes, etc.) etc.), it is difficult to handle nickel-titanium alloy components with complex structures

However, at present, the method of simply using aging strengthening or grain refinement to improve the strength of the nickel-titanium shape memory alloy matrix has no obvious effect, and is not suitable for processing nickel-titanium alloy components with complex structures.

Images