Method for representing recovery characteristics of Fe-Mn-Si-based memory alloy by in-situ X-ray diffraction

Abstract

The invention discloses a method for representing recovery characteristics of a Fe-Mn-Si-based memory alloy by in-situ X-ray diffraction. In the method, in-situ X-ray diffraction analysis is introduced to the inverse phase change process of the Fe-Mn-Si-based memory alloy, thus phase change characteristics of conversion from martensite to austenite under stress induction in the heating shape recovery process of the Fe-Mn-Si-based memory alloy can be represented synchronously in real time through high-temperature in-situ X-ray diffraction. The method mainly comprises the steps of: pretreating a sample and carrying out X-ray diffraction on the pretreated sample by utilizing a high-temperature in-situ sample platform so as to obtain an in-situ X-ray diffractogram representing the shape memory recovery characteristics of the Fe-Mn-Si-based memory alloy. By using the method disclosed by the invention, phase change characteristics of the Fe-Mn-Si-based memory alloy can be presented from a macroscopic perspective, and the change of structure in the recovery process is synchronously, in situ and visually researched through diffraction pattern analysis.

Description

technical field [0001] The invention relates to a method for characterizing recovery properties of Fe-Mn-Si-based memory alloy by in-situ X-ray diffraction. Background technique [0002] Fe-Mn-Si-based memory alloy is a memory alloy material developed since the 1980s with the advantages of low price and easy processing. The shape memory effect of Fe-Mn-Si based memory alloys is realized by stress-induced γ(fcc)→ε(hcp) transformation during deformation and ε(hcp)→γ(fcc) inverse phase transformation during heating. [0003] Most of the existing studies on the structure and phase transition of Fe-Mn-Si-based memory alloys use optical microscopes, scanning electron microscopes and transmission electron microscopes to observe the microstructure. Such analysis is very mature, but its limitation is that it is only at the micron level The microscopic perspective at the nanoscale reveals the microstructure and morphology changes of memory alloys during deformation and deformation re...

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Problems solved by technology

[0003] Most of the existing studies on the structure and phase transition of Fe-Mn-Si-based memory alloys use optical microscopes, scanning electron microscopes and transmission electron microscopes to observe the microstructure. Such analysis is very mature, but its limitation is that it is only at the micron level And nano-scale microscopic perspective reveals the microstructure and morphology changes of the memory alloy during deformation and deformation recovery. The sample preparation is complicated, and it is difficult to perform dynamic analysis.

Later, it was reported that the recovery process of shape memory alloys was characterized by atomic force microscopy, and the scale range was also at the micron level. These methods cannot achieve macroscopic characterization, and it is difficult to accurately present the Fe-Mn-Si matrix from a macroscopic perspective. For the phase transition characteristics of memory alloys, it is difficult to draw conclusions from the perspective of the material as a whole for the analysis of microstructures such as stacking faults. Quantitative analysis also shows the limitations of electron microscope analysis.

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