形状记忆合金的细观力学本构模型

定义了一个能反映形状记忆合金超弹性和形状记忆效应的概念：形状记忆因子．利用相变过程中自由能与马氏体体积分数之间的微分关系,推导了形状记忆因子演化方程．从细观力学角度建立了一个考虑马氏体择优取向过程的形状记忆合金三维本构模型．与功能相同的现有模型相比,该模型具有更简单的数学表述和清晰的物理意义．     

NiAl合金的高温形状记忆效应SCIEI

观察到Ｎｉ－３４．６ａｔ．－％Ａｌ薄带单程和双程形状记忆效应（ＳＭＥ），单程ＳＭＥ发生在３００℃以上并具有很好的形状恢复率（１００％）。经高温退火后合金中产生了体积分数为１６％的延性γ′－Ｎｉ_３Ａｌ沉淀相、延性和韧性有进一步改善，同时发现退火后的薄带也具有良好的单程和双程高温ＳＭＥ。结果表明富Ｎｉ的ＮｉＡｌ有可能成为新型高温形状记忆合金（ＳＭＡ）。     

SHAPE MEMORY EFFECT OF POLYCRYSTALLINE Fe-Mn-Si ALLOYS

The influence of quenching temperature on the shape memory effect(SME)of theFe-Mn-Si polycrystalline alloys and their martensitic transformation temperature have beenstudied.The SME of the hot-rolled specimen may be remarkably enhanced by selectingquenching temperature of 600—800℃.It has been shown that SME is influenced not only bythe distribution of ε-phase morphology but also by its pre-existence.     

Fe-Mn-Si多晶合金的形状记忆效应

本文研究了Fe-Mn-Si多晶合金的形状记忆效应(SME)与淬火温度的关系,以及马氏体转变点的变化。发现热轧样品经600—800℃处理后,记忆效应显著提高。形状记忆效应不仅受到ε相形态分布的影响,还与预存ε相的多寡有关。     

DEFORMATION OF CuZnAl SHAPE MEMORY ALLOYS IN MARTENSITIC STATE

Plastic deformation of three CuZnAl shape memory alloys in martensitic state was investi-gated by means of optical and electron metallography,dilatometry and electric resistiviy de-termination.Two of the alloys are in martensitic state at ambient temperature,and theA_f temperature of the third one is far below the ambient temperature.The effect ofdeformation of alloys in martensitic state on the course and temperature of transformation aswell as the hysteresis of transformation cycles has been analyzed and the “effect of the firstcycle” has also been discussed.     

COMPOSITION TRIANGLE DIAGRAMS OF Ni-Mn-Ga MAGNETIC SHAPE MEMORY ALLOYS

A statistical work has been done to collect the composition ranges of Ni-Mn-Ga alloys exhibiting different structures and martensite start temperature （M,）, large magnetostrain or the co-existence of magnetic and structural transitions. The alloys with five-layered （5M）, seven-layered （7M） modulated and non-modulated （T） martensitic structures were mapped in the graph. An empirical formula has been presented to reflect the effect of elements nickel （Ni ）, manganese （ Mn ） and gallium （Ga）, on the martensite start temperature （M3）. The martensitic structure is sensitive to the composition and the martensitic transformation temperature is most drastically affected by the Ni content. The alloys with large magnetostrain or co-existence effect of the magnetic and structural transitions were also listed in a limited area.     

Cu—Zn—Al形状记忆合金在马氏体状态的塑性变形

采用光学显微镜、电子显微镜、电阻和膨胀方法研究了三种Cu-Zn-Al形状记忆合金在马氏体状态的塑性变形对马氏体转变温度、相变过程及转变循环滞后的影响。其中两种合金相变温度较高,在室温下即为马氏体状态。第三种合金A_f温度远低于室温。讨论了“第一次循环效应”的可能机制。     

DESIGN CONCEPT FOR SNAP-ACTING TWO-WAY SHAPE MEMORY DEVICES

Snap-acting two way shape memory device can be obtained by using the design proposed byauthors.Some essential parameters which characterize the properties of device have been pro-posed also in this paper.And the principle and method according to which a practicalsnap-acting device can be designed have been described.     

速动形状记忆合金元件设计原理

提出了评价速动双程形状记忆元件性能的主要参数,并说明了设计实用速动元件的原理和方法。     

EXPERIMENTAL AND THEORETICAL INVESTIGATION OF PSEUDOELASTIC HYSTERESIS IN SHAPE MEMORY ALLOYS

1.IntroductionAnimportantaspectwithintheresearchonshapemellloryalloysisprovidedbytheinvestigationofthehysteresisbehavior,whichappearsillstress--strailldiagram,straintemperaturediagramandstress--temperaturediagram[ll.Insomeapplicationsthehysteresisiswelcomeandonelikesittobewide.Thisisthecase,ifoneusesshapememoryalloysforclamsandsplints,asinthemedicalfi.ld[2]orforcouplings[3].Inotherapplicationsthehysteresisisincollvenient,becauseitimpliesdissipation.Thusinmanyoftheproposedheatenginesworkingwit…     

Ni-Ti形状记忆合金中母相(?)马氏体可逆转变过程的研究SCIEI

用透射电镜对Ni-Ti形状记忆合金中母相?马氏体可逆转变进行了动态观察。利用高分辨电子显微术研究了该合金相变温度上下的结构变化。结果表明,马氏体与奥氏体的取向关系为:[111]_A∥[110]_M,[110]_A∥[001]_M,(110)_A∥(001)_M,(110)_A与(010)_M间夹角为6.5°左右;马氏体的晶体缺陷多为孪晶和层错,新发现有孪晶而为(100)的孪晶。     

REVERSIBLE TRANSFORMATION BETWEEN MATRIX AND MARTENSITE IN Ni-Ti SHAPE MEMORY ALLOYS

The reversible transformation between matrix and martensite in Ni-Ti shape memory alloyshas been dynamically observed under TEM.The orientation relation between martensite andaustenite as well as the structural change near the transition temperature has been also studiedwith the help of HREM SADP.The results show that the orientation relation betweenmartensite and austenite is[(?)11]_A//[(?)10]_M,[110]_A//[001]_M,(110)_A//(001)_M and theangle between((?)110)_A and(010)_M is about 6.5°.The crystal defects of martensite are foundto be twin and stacking fault,and the twin plane as(100).     

EFFECTS OF THERMAL CYCLES ON THE PROPERTIES OF CuZnAl SHAPE MEMORY ALLOYS

１．ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｍｐａｒｅｄｗｉｔｈＮｉＴｉｓｈａｐｅｍｅｍｏｒｙａｌｌｏｙｓ,ＣｕＺｎＡｌｓｈａｐｅｍｅｍｏｒｙａｌｌｏｙｓａｒｅｍｕｃｈｃｈｅａｐｅｒａｎｄｃａｎｂｅｍａｃｈｉｎｅｄｅａｓｉｌｙ．Ｒｅｃｅｎｔｌｙｔｈｅｙｈａｖｅｂｅｅｎｒｅｓｅａｒｃｈｅｄａｎｄｄｅｖｅｌｏｐｅｄｗｉｄｅｌｙ．Ｔｈｅａｌｌｏｙｓｈａｖｅｂｅｅｎｕｓｅｄｉｎｍａｋｉｎｇｔｅｍｐｅｒａｔｕｒｅｃｏｎｔｒｏｌｐａｒｔｓ,ｗｈｉｃｈｈａｖｅｂｏｔｈｆｅｅｌｉｎｇｔｅｍｐｅｒａｔｕｒｅａｎｄｄｒｉｖ…     

PHASE TRANSFORMATIONS IN RAPIDLY SOLIDIFIED TiNi SHAPE MEMORY ALLOYS

ＰＨＡＳＥＴＲＡＮＳＦＯＲＭＡＴＩＯＮＳＩＮＲＡＰＩＤＬＹＳＯＬＩＤＩＦＩＥＤＴｉＮｉＳＨＡＰＥＭＥＭＯＲＹＡＬＬＯＹＳＷａｎｇ；ＳｈｉｄｏｎｇＷｕ；Ｘｉａｏｚｈｅｎ（ＡｎａｌｙｔｉｃａｎｄＴｅｓｔｉｎｇＣｅｎｔｅｒ．ＳｏｕｔｈｅａｓｔＵｎｉｖｅｒｓ...     

ENFLUENCE OF DEFORMATION AT MARTENSITE STATE ON SHAPE RECOVERY IN CuZnAl MEMORY ALLOYS

An investigation of the influence of deformation on shape recovery has been put forward inCu-Zn-Al shape memory alloys.Starting at a model of the re-orientation of martensitic va-riants,the principle and essentiality of the influence of the amount of pre-deformation ε onshape recovery rate η is elucidated.     

近等原子比NiTi形状记忆合金的超弹性

研究了冷拔量、热处理工艺参数对Ｔｉ４９．８％Ｎｉ合金丝材的超弹性的影响。结果表明不同冷拔量、不同退火工艺处理的丝材获得完全超弹性的温度区间、超弹性特性都不相同，获得最大超弹性应变量的处理工艺为冷拔量３９％、退火温度７２３Ｋ、保温时间３０ｍｉｎ。     

形状记忆合金的剪切本构模型

利用形状记忆因子的概念,建立了用于描述纯剪切状态下形状记忆合金(SMA)相变行为的形状记忆演化方程.在假设SMA为各向同性材料和利用三维细观力学本构方程的前提下,推导了纯剪切状态下SMA的力学本构方程.所建立的形状记忆演化方程和力学本构方程中的材料常数均可以通过宏观实验来测定,便于工程实际中的应用.数值计算结果表明,所建立的形状记忆演化方程能正确地描述纯剪切状态下SMA发生在奥氏体、孪晶马氏体和非孪晶马氏体间的相变行为,力学本构方程可再现形状记忆效应和超弹性的热力学过程.     

应力制约双程形状记忆材料的相交特性

利用应力对双程形状记忆(TWSM)材料相变的制约作用,在NiTi合金TWSM材料中实现速动相变和速动TWSM效应。研究了应力场的形式、大小对热滞回线的影响;计算了相变驱动力ΔG_c随温度变化的关系并给出速动相变的热力学解释。     

(NiTi)_(50-0．5x)Nb_x形状记忆合金的阻尼性能及力学性能

通过加入Nb制备了具有双相组织的(NiTi)50-0.5xNbx(x=5,10,15,20)形状记忆合金,合金兼具高阻尼性能和高屈服强度.随着Nb含量x的增大,合金中(NiTi+β-Nb)共晶组织比例含量增加,合金轧制样品在马氏体状态自协作屈服强度随之升高,在x=15时达到最高(289 MPa);同时,合金轧制样品保持高阻尼性能,本征阻尼性能tan δ＞0.01,并随x增大而升高.根据形状记忆合金阻尼理论以及NiTiNb形状记忆合金的阻尼性能随温度的变化规律,探讨了β-Nb和NiTi相界面阻尼对合金阻尼性能的影响.     

PREPARATION OF TiNi SHAPE MEMORY ALLOY POROSINT BY SHS

ＰＲＥＰＡＲＡＴＩＯＮＯＦＴｉＮｉＳＨＡＰＥＭＥＭＯＲＹＡＬＬＯＹＰＯＲＯＳＩＮＴＢＹＳＨＳ①ＣｈｕＣｈｅｎｇｌｉｎ，ＬｉＢｏ，ＷａｎｇＳｈｉｄｏｎｇ，ＺｈａｎｇＳｈｕｇｅ，ＹａｎｇＸｉａｏｘｉ，ＹｉｎＺｈｏｎｇｄａＢｏｘ４...