Shape memory alloy thermal mechanical fatigue test device

Abstract

A shape memory alloy thermal mechanical fatigue test device is used for being matched with an MTS tester to conduct a shape memory alloy thermal mechanical fatigue test. An MTS controller 2 controls the acquisition and processing of force and strain data. A sample chuck of the MTS tester is connected with a sample 8 to be tested through an insulating clamping device 10, the output end of a controllable electric heating power supply 4 is connected to the two ends of the sample 8 to be tested in a straddling mode, a temperature signal is input into the MTS controller 2 through a temperature sensor used for measuring the instant temperature of the sample to be tested, and a temperature controller 7 controls on-off of the power supply 4 to enable the sample to be tested to be at a set temperature. The test device for thermal mechanical fatigue study of a shape memory alloy material is provided, temperature rising and lowering circulation of the material can be achieved effectively, temperature rising inside and outside the material is even, insulation between the test device and a hydraulic tester is achieved, and synchronous acquisition of force, temperature and strain data is achieved.

Description

technical field [0001] The invention belongs to the technical field of thermodynamic performance testing of shape memory alloys, in particular to the thermomechanical fatigue failure behavior of shape memory alloys. Background technique [0002] In the past 30 years, Xingxing's smart alloy materials have attracted many scholars at home and abroad to conduct research. Among them, shape memory alloys are widely used in machinery, medical, aviation, automobile and other industries because of their good biocompatibility, light weight and wear resistance, and unique shape memory properties. The shape memory property refers to the process in which a material or structure undergoes loading deformation at low temperature, and the residual deformation after unloading gradually returns to the state before loading after heating up. During the service process of materials or structures, reciprocating shape memory effects often occur, and materials must undergo repeated loading-unloadin...

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Problems solved by technology

Simultaneous recording of force, temperature and strain data is difficult with traditional heating methods

[0007] 4) In the shape memory thermomechanical fatigue test, the strain response during the heating-cooling process is very large, and it is necessary to precisely control the mechanical load during the heating-cooling process. If the combination of resistance heating and mechanical testing machine is used, the current Flowing into the testing machine will affect the hydraulic control system of the testing machine. If the current flows into the strain extensometer, it will affect the measurement accuracy of the strain sensor and make its readings fluctuate constantly. Therefore, the insulation problem needs to be solved

[0008] With the wide application of the shape memory effect of shape memory alloys, it is extremely important to study the fatigue failure of the shape memory effect of materials and then predict the fatigue life. The existing experimental methods may only obtain the stress, strain and temperature curves of a single cycle. It is impossible to carry out fatigue failure test, or the traditional temperature box is used for heating, which makes the test cycle longer, and the temperature data is not suitable for collection, and the stress, strain and temperature curves of multiple cycles cannot be obtained, or the force or force cannot be accurately controlled when performing multiple cycle experiments. Displacement, the error of the experimental results is large, and it is impossible to reveal the law of the material shape memory effect in the fatigue cycle process

So far, there is still a lack of an efficient and precise device for performing thermomechanical cycle fatigue experiments on shape memory alloy materials.

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