Cu-Zn-Al 形状记忆合金热弹性马氏体相变临界驱动力的估算

发展了新的估算 Cu-Zn-Al 合金热弹性马氏体相变临界驱动力方法。由测量合金的杨氏模量及估算马氏体内的储存能量(层错能),所得的临界驱动力数值与量热法测得热效应后换算的近似值非常接近。     

Cu-Zn-Al 形状记忆合金马氏体相变热力学

对不同成分的 Cu-Zn-Al 合金中无序α与β相的平衡温度 T_0~*,有序α′与β′相的平衡温度 T_0(母相为 L2_1有序结构)及各种有序母相所得 M_s 进行了系统的计算。用电阻法测试了直接淬火及分级淬火试样的相变温度。结果表明,当母相为 L2_1有序结构时,理论计算的 M_s 值与分级淬火试样 M_s 的实验值吻合。计算还证明,相对无序结构母相 B2或 DO_3有序化均引起 M_s 下降,前者使 M_s 下降更多。     

Cu-Zn 合金马氏体相变热力学

假定 Cu-Zn 合金马氏体相变中新、旧原子存在 Bain 机制所示的对应关系,则沿用已知的热力学数据,以 BWG 模型处理 Cu-Zn 合金的有序问题,推导出相变驱动力ΔG~(β′→α′)的普遍表达式。以该式计算了Cu-Zn 合金马氏体相变的平衡温度 T(?)及马氏体相变点 M_s,其中 M_s 与实验结果很好吻合。计算证明,母相有序化是 Cu-Zn 合金发生热弹性马氏体相变的必要条件,有序度对 M_s 有显著的影响。     

β—NiAl合金的马氏体相变与形状记忆效应

介绍了β－ＮｉＡｌ金属间化金属间化合物的热弹性马氏体相变与形状记忆效应及其韧化途径。     

Cu—Al 合金马氏体相变热力学

依据规则溶液模型,在充分利用 Cu-Al 系相图的基础上,导得 Cu-Al 合金的一些热力学参量。应用统计模型处理了 Cu-Al 合金中涉及马氏体相变的体心立方及面心立方两种结构的有序相变,直接从理论上计算了不同成分 Cu-Al 合金α和β相的平衡温度 T~*,有序α′与β′相的平衡温度 T_0,以及马氏体相变点 M_s,其中 M_s 与实验值非常吻合。计算还表明 Cu-Al 系中 T_0比 T_0~*更高。     

CuZnAl合金淬火和时效的正电子湮没研究──关于热弹马氏体稳定化原因的讨论

用正电子湮没Ｄｏｐｐｌｅｒ展宽能谱仪和寿命仪研究了一种淬火和时效后的ＣｕＺｎＡｌ形状记忆合金,对结果的分析认为：热弹马氏体稳定化的主导因素以空位运动为好。     

形状记忆Fe—Mn—Si合金中马氏体相变和扭转形变的恢复

研究了Ｆｅ－２９．４４Ｍｎ－６．２０Ｓｉ合金中的ｒ→←ε相变和顺磁性→→反铁磁性转变（以下简称磁转变）。用电阻测量跟踪了此过程。用Ｘ射线珩射法（ＸＲＤ０作了相分析。硅急剧增加六方相的电阻率，ε→ｒ相变表现为电阻降低，ｒ→ε转变表现为电阻升高。ＸＲＤ表明，淬火后样品除ｒ相外有少量六方ε相。扭转形变恢复率与形变量和形变前无热诱发马氏体存在有很大关系。     

Co-Ni合金磁诱发马氏体相变的热力学分析

从应力诱发马氏体相变热力学出发，分析了外磁场作用下具有高磁晶各向异性能的Co-Ni合金的磁诱发马氏体相变热力学，并建立了相应的数学模型。     

CuZnAl（RE）形状记忆合金马氏体稳定化研究

采用定量金相,电子探针,扫描电镜,电阻法,透射电镜等方法,研究了复合稀土对ＣｕＺｎＡｌ形状记忆合金中马氏体稳定化的影响。实验结果表明,加入复合稀土以及采取合理的热处理工艺,可有效地防止马氏体稳定化。当合金发生马氏体稳定化后,经过重新处理及热循环训练,合金仍能恢复较好的形状记忆性能。     

Positron Study of Origin of Thermoelastic MartensiteStabilization for a Cu-Zn-Al Alloy

A series of Cu-23Zn-10Al (at pct) alloy specimens subjected to different heat-treatment processes have been studied by means of Doppler broadening technique of positron annihilation combined with mechanical test. Results show that the mechanism of quenched-in vacancies, instead of the other suggested ones, plays a dominant role in thermoelastic martensite stabilization of Cubased shape memory alloy. Knowing the character of the movement of quenched-in vacancies and eliminating them as rapidly as possible are the basis for further optimizing heat-treatment process to obtain desired shape memory performance     

Crossed Micro-bands in the Martensite Variant Pairs of a Thermomechanically Trained Cu-Zn-Al Alloy

The crossed micro-bands in the martensite variant pairs of a thermomechanically trained Cu25.66Zn-4.02Al (wt-%) alloy have been studied. It was found that the micro-bands pass through the interface from one martensite variant to another and their orientation inside different variants is distinct, which would remain in the parent phase after the reverse transformation and play an important role in the formation of preferential martensite. In fact, the crossed micro-bands are micro-twins for accommodating the stress fields generated during thermomechanically training     

固体电子论分析CuZnAl记忆合金有序转变与马氏体稳定化

应用固体经验电子理论，计算了ＣｕＺｎＡｌ记忆合金中第４组元Ｎｉ和Ｍｎ对Ａ＿２→Ｂ＿２和Ｂ＿２→ＤＯ＿３两种有序转变温度的影响。计算得出：Ｎｉ提高而Ｍｎ降低合金的有序转变温度。这与Ｎｉ和Ｍｎ对合金的马氏体稳定化影响的趋势一致。表明固体电子论可以说明ＣｎＺｎＡｌ合金的稳定化和用来指导探索记忆性能好的合金。     

Mobility of Various Intervariant Interfaces in 18R Martensite in a Cu-Zn-Al Alloy Part Ⅰ: In-situ Observations

The motion of intervariant intedeces under the action of applied stress in the internally faulted 18R martensite in a Cu-Zn-Al shape memory alloy has been studied. Transmission electron microscopy in situ observations show that the interfaces between 24 martensite variants have different reaction to applied stress. The A/C type and A/B type interfaces have good mobil-ity, the A/D type interface has bad mobiIity, and the different-group-intervariant interfaces are basically immobile.     

时效过程Cu－Zn－Al合金阻尼特性的研究

本文研究了热处理工艺对Ｃｕ－１４．１４Ｚｎ７．９７Ａｌ（ｗｔ％）合金自然时效阻尼特性的影响。合金的阻尼性能依赖于分级淬火参数Ｔ＿ｂ及ｔ＿ｂ且随时效时间的延长存在“峰效应”。Ｔ＿ｂ＝２００℃的分级淬火减少了时效过程中阻尼的损失，使合金处于稳定的高阻尼状态。Ｘ－ｒａｙ衍射分析表明，合金在自然时效时其结构有序度发生改变且有α相析出。合金阻尼特性的波动与空位等点缺陷和界面的相互作用及α相的析出有关。     

A Crystallography Study of Bainitic Transformation in a Cu-Zn-Al Alloy

The crystallographic nature of initialisothermal phase transformation in Cu-26Zn-4Al(wt-％) was investigated. The kinetic transforma-tion curve, morphology, crystal structure,substructure, orientation relationship and twinrelationship of bainite plates have been studiedby means of optical and transmission electronmicroscopy. The experimental results showedthat the characteristics of initial 8→bainitetransformation are not exactly consistent withthat found in martensite transformation, forexample, orientation relationship between matrixand bainite does not exist in martensitetransformation.