Phase Transformations and Martensite Stabilization in Ni2.36Mn0.64Ga High-Temperature Shape Memory Alloy

Q4 Physics and Astronomy

Defect and Diffusion Forum Pub Date : 2023-12-12 DOI:10.4028/p-oqvVm1

A.A. Shcherbakov, R.A. Vasin, A. Balagurov, Vladimir V. Khovaylo, I.S. Golovin

引用次数: 0

Abstract

We report on experimental investigations of a Ni2.36Mn0.64Ga Heusler alloy, which transforms to tetragonal martensite at cooling below Ms ≈ 271°С. The evolution of lattice constants was tracked by in situ neutron diffraction measurements. It was found that the martensite tetragonality c/a gradually decreases during heating from room temperature to austenite transition start temperature As ≈ 272°С. The phenomenon of martensite stabilization was investigated by differential scanning calorimetry utilizing three different protocols of the martensite aging. It was found that the martensite aging at a constant temperature T = 255°С merely shifts the reverse transformation to higher temperatures, while the reverse transformation temperature interval (Af – As) remains the same (≈ 30°C) independently of aging time. On the other hand, a multistep aging at different temperatures starting from T = 255°С not only shifts the reverse transformation temperature, but makes the transformation temperature interval narrower down to As – Af ≈ 10°C.

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Ni2.36Mn0.64Ga 高温形状记忆合金中的相变和马氏体稳定化

我们报告了对 Ni2.36Mn0.64Ga Heusler 合金的实验研究，这种合金在冷却到 Ms ≈ 271°С 以下时会转变为四方马氏体。通过现场中子衍射测量跟踪了晶格常数的演变。结果发现，在从室温加热到奥氏体转变起始温度 As ≈ 272°С的过程中，马氏体的四方性 c/a 逐渐减小。利用三种不同的马氏体时效方案，通过差示扫描量热法研究了马氏体的稳定现象。结果发现，在恒温 T = 255°С 下进行马氏体时效只是将反向转变转移到更高的温度，而反向转变温度区间（Af - As）保持不变（≈ 30°C），与时效时间无关。另一方面，从 T = 255°С 开始在不同温度下进行多级老化，不仅会使反向转化温度发生变化，还会使转化温度区间缩小到 As - Af ≈ 10°C。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Defect and Diffusion Forum Physics and Astronomy-Radiation

CiteScore

1.20

自引率

0.00%

发文量

127

期刊介绍： Defect and Diffusion Forum (formerly Part A of ''''Diffusion and Defect Data'''') is designed for publication of up-to-date scientific research and applied aspects in the area of formation and dissemination of defects in solid materials, including the phenomena of diffusion. In addition to the traditional topic of mass diffusion, the journal is open to papers from the area of heat transfer in solids, liquids and gases, materials and substances. All papers are peer-reviewed and edited. Members of Editorial Boards and Associate Editors are invited to submit papers for publication in “Defect and Diffusion Forum” . Authors retain the right to publish an extended and significantly updated version in another periodical.