Ordering and Martensitic Transformations of the Cu-Al-Mn Base Shape Memory Alloys.

Cu-Al-Mn 基形状记忆合金的有序化和马氏体转变。

• 批准号: 08650806
• 负责人: KAINUVA Ryosuke
• 金额: $ 0.58万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650806/
• 关键词: SHAPE MEMORY; Cu-Al-Mn SYSTEM; ORDER-DISORDER TRANSITIONS; MARTENSITIC TRANSFORMATIONS

The shape memory (SM) effect due to the thermoelastic transformation has been investigated for 30 years, and it is generally noticed that the origin of the SM effect has been already clarified. Recently, we found in the Cu-Al-Mn alloys that a fully disordered bcc phase which transforms a disordered fcc phase shows an almost perfect SM effect. This result is peculiar against a common sense on the mechanism of the SM effect.The purpose of this study is to clarify an origin of the perfect SM effect of the disordered Cu-Al-Mn alloys by crystallographic and thermodynamic analysis. The Pbtained results are as follows :(1) The crystal structures of the parent and martensite phases have been determined. Alloys with high Al content over 17at% transform from the parent A2 (bcc) to martensite Al (fcc) structure, and those under 16at% transform from the L21 to 18R structure.(2) It has been clarified that volume change by the A2/A1 transformation is very small less than 1% and the transformation is thermoelastic.(3) The SM properties of many alloys have been examined. It has been clarified that the most alloys with the Al content over 14at% show an excellent SM effect.(4) A thermodynamic analysis of the stability of ordered phase has been performed Bragg-Williams-Gorsky model and pair interaction energies between Cu, Al, and Mn were determined.(5) Enthalpy changes due to short-range ordering have been estimated on the basis of the result of (4). It was clarified that values of the enthalpy changes are comparable to enthalpy changes due to the A2/A1 martensitic transformations.All these results suggest that the short-range ordering is enough to give a reversibility on the lattice correspondence between the parent and martensite lattices, resulting in the SM effect.

由热弹性相变引起的形状记忆效应已经研究了30年，人们普遍注意到形状记忆效应的起源已经澄清。最近，我们发现在Cu-Al-Mn合金中，由无序fcc相转变为完全无序bcc相，表现出近乎完美的SM效应。本研究的目的是通过晶体学和热力学分析来阐明无序Cu-Al-Mn合金的完美SM效应的起源。主要结果如下：（1）测定了母相和马氏体相的晶体结构。当Al含量大于17at%时，合金由母相A2（bcc）转变为马氏体Al（fcc）组织，当Al含量小于16at%时，合金由L21转变为18 R组织。(2)已经阐明，由A2/A1转变引起的体积变化非常小，小于1%，并且转变是热弹性的。(3)许多合金的SM性能已被检查。结果表明，Al含量大于14at%的合金具有良好的SM效应。(4)用Bragg-Williams-Gorsky模型对有序相的稳定性进行了热力学分析，确定了Cu、Al、Mn之间的相互作用能。(5)根据（4）的结果估算了短程有序化引起的焓变化。这些结果表明，短程有序足以使母晶与马氏体晶格对应关系可逆，从而产生SM效应。

项目成果

X.J.Liu: "Phase Equilibria in the Cu-rich portion of the Cu-Al-Mn Binary System" J.Alloys and Compounds. (in press). (1998)

X.J.Liu：“Cu-Al-Mn 二元体系中富铜部分的相平衡”J.合金与化合物。

R.Kainuma: "Phase equilibria and heusler phase stability in the Cu-rich portion of the Cu-Al-Mn system" J.Alloys & Compounds. (発表予定). (1998)

R.Kainuma：“Cu-Al-Mn 系统富铜部分的相平衡和赫斯勒相稳定性”J.合金与化合物（即将发表）。

貝沼 亮介: "Cu-Al-Mn系ホイスラ-合金における相安定性と機械的性質" 日本伸銅技術研究会誌. 35. 211-215 (1996)

Ryosuke Kainuma：“Cu-Al-Mn Heusler 合金的相稳定性和机械性能”日本铜轧制技术研究会杂志 35. 211-215 (1996)。

R, Kainuma: "Phase equilibria and heusler phase stability in the Cu-rich portion of the Cu-Al-Mn system" J.Alloys & Compounds,. (印刷中). (1998)

R，Kainuma：“Cu-Al-Mn 体系中富铜部分的相平衡和赫斯勒相稳定性”J.Alloys＆Compound，（1998 年出版）。

R, Kainuma: "Thermoelastic Martensite and Shape Memory Effect in Ductile Cu-Al-Mn Alloys" Metall.Mater.Trans.27A. 2187-2195 (1996)

R，Kainuma：“延性 Cu-Al-Mn 合金中的热弹性马氏体和形状记忆效应”Metall.Mater.Trans.27A。