FeMnSi形状记忆合金管接头的研制

以开发实用ＦｅＭｎＳｉ形状记忆合金管接头为目的,主要研究了管接头的成型性,处理制度、耐蚀性能和密封性能。结果表明：ＦｅＭｎＳｉ合金耐蚀性能差,合金中Ｓｉ含量严重影响接头成型性,经最佳热处理,管接头的形状恢复率达到５５％,接管的耐压达３２ＭＰａ,适用于低压管路连接。要扩大其应用范围,需提高合金的耐蚀性能和接头的形状恢复率。     

减压式先导阀的研制及性能分析

对研制的减压式先导阀进行了静态性能分析，阐述了该阀的工作原理、结构设计，并进行了实验验证。     

前苏联研制TiNi形状记忆合金现状

形状记忆合金是一种过去人们尚未认识的物理-机械性能的新型合金,合金的奇特功能可解决许多工程上的问题,因此倍受各国科学家的重视,并相继对合金基础理论及其应用开展研究。合金的形状记忆是由热弹性马氏体转变引起的,据称这一现象是在1949年前苏联学者Г.В.库尔纠莫夫和Л.Г.汉德罗斯所发现。TiNi形态记忆合金     

形状记忆合金薄膜

新近研究资料表明,Ｔｉ－Ｎｉ溅射薄膜具有与整体形状记忆合金完全相同的形状记忆及超弹性性能。本文就形状记忆合金薄膜的制作、薄膜的组织、形状记忆及超弹性性能、形状记忆合金薄膜的应用等作一综述。     

直线式先导阀自动火焰钎焊机的研制

先导阀是空调四通阀的重要组成部件,其质量的好坏直接影响到空调四通阀的工作稳定性乃至空调质量.其零件采用薄板冲压成型,部件采用全钎焊装配.先导阀结构如图1所示.     

形状记忆合金热机械稳定性测试仪的研制

介绍了形状记忆合金热机械稳定性测试仪研制中的有关问题。包括环境温度、应力大小、响应时间和功率的确定以及整机的硬件、软件系统。该装置的冷热循环温度范围：－１５０℃～＋１２０℃，形变次数计算范围１～９９９９，最大载荷２０ｋｇ，最大位移５０ｍｍ，位移测量精度为±０．１ｍｍ。用该仪器记录的曲线可用来研究合金记忆性能的变化、临界负荷及使用寿命等评价记忆合金特性的实用参数。     

NiTi形状记忆合金螺钉的研制及医学应用

成功地研制了一种新型NiTi形状记忆合金螺钉并已临床应用了150例,经3年多考核,未发现骨不连及股骨头缺血坏死现象。     

NiTi形状记忆合金在冷热水混水阀中的应用

日本大同特殊钢（株式会社）于1992年开始了用形状记忆合金作为混水阀卷簧的研究开发。当时，市场上销售的带水温自动调节功能的混水阀中，感温元件用的是导热性能较差的液体石蜡，对温度变化的响应速度较慢。暂时关水后再打开水龙头时，因进水温度变化所导致的出水温度的波动较大，可达5～10℃。用形状记忆合金卷弹簧作为感温元件可以有效地改善导热性。在混水阀中，主要利用的是形状记忆合金在相变区域内的形状回复特性，因此，必须解决相变温度的控制和产生的作用力的控制等许多技术课题。     

高压气动开关阀的特性分析

介绍了一种研究高压气动开关阀动态特性的细分原理；根据细分原理，利用MATLAB的Simulink子系统技术，建立了分别包含控制腔定容积、变容积和余隙容积等三个单元模块的高压气动开关阀的开启和关闭过程的仿真模型，对高压气动开关阀进行了仿真；仿真结果与实验测试结果的良好吻合，证明了细分原理的正确性。     

形状记忆合金的开发

利用燃烧合成法制造的镍钛形状记忆合金〔1〕　镍钛形状记忆金属间化合物 (合金 )由于其构成元素之间的比重差很大 ,在传统熔炼过程中容易发生重力偏析所以很难制得成分均匀的材料。因此 ,发展了利用其构成元素单体粉末之间的反应来制取这种金属间化合物的燃烧合成技术。但是这种金属间化合物较之铁系金属材料 ,其塑性加工极难 ,因此 ,研究了利用燃烧合成法制得的镍钛形状记忆合金的塑性加工性能。研究用的原材料粉末是工业上最常用的粒度 <15 0 μm的纯钛粉和粒度为 8～ 15 μm的纯镍粉 (INCO镍 )。以Ni过量的TiNi组成比配好的粉末混合…     

Machinability and surface integrity of Nitinol shape memory alloy

Nitinol shape memory alloys have wide applications in medical devices and actuators. However, the unique mechanical properties including superelasticity, high ductility, and severe strain-hardening make Nitinol exceedingly difficult to cut. This work determines dynamic mechanical behaviors of Nitinol in cutting. It is found that the very high strength and specific heat are responsible for large flank wear and fast tribo-chemical crater wear, respectively. The austenitic white layer in cutting is caused by deformation, while the twinned martensitic white layer is caused by quenching in EDM. Alloying from tools is negligible in cutting but unavoidable even in finish EDM trim cut.     

Compressive training of the shape memory alloy washer

This paper evaluates the performance and engineering aspects of 44Ti-47Ni-9Nb alloy in a pretensioning washer application. Previously the behavior of this alloy has mainly been studied for tensile predeformation with wires and strips up to 1 mm thickness. The present work investigated the effect of compression deformation and different homogenization temperatures on ring-shaped washers with larger dimensions. The best results with the compression-trained washer were achieved after homogenization at 1073 K where the compression training deformation was -10.4%, the lowest applied. The deformation training was carried out at 213 K near the martensitic reaction start temperature of the material. The expansion method, applied to the commercial reference ring, seemed to be a fairly efficient training method for the studied application, even though the parallel course of the radial surfaces was poor.     

Martensitic transformation and magnetic properties of Ti-doped NiCoMnSn shape memory alloy

Martensitic transformation, microstructure, and magnetic properties of Ti-doped Ni43-xTixCo7Mn43Sn7（at%）（x = 0, 0.5, 1.0, 2.0, and 4.0） shape memory alloys were investigated. The results show that transformation temperatures of Ni43Co7Mn43Sn7 can be efficiently adjusted by the substitution of Ti for Ni. For example, the martensitic transformation starting temperature（Ms） is reduced by about 278 K with 4 at% addition of Ti. Room temperature microstructure evolves from single tetragonal martensite for the Ti-free alloy to dual phases（tetragonal martensite ＋ second phase） with 0.5 at%, 1.0 at%, and2.0 at% addition of Ti to dual phases（cubic austenite ＋ second phase） for 4.0 at% Ti-doped alloy. The mechanical properties can be obviously improved by adding an appropriate amount of Ti. A noteworthy point is that magnetic-field-induced reverse transformation is observed in Ni39Ti4Co7Mn43Sn7 alloy.     

Twice reverse shape memory effect in CuZnAl shape memory alloy

The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction, %) alloy upon successive heating (the rate of heating is 5℃/min) have been studied by means of ρ-T curve , shape memory effect measurement, optical metallographical observation and X-ray diffraction. The first abnormal reverse shape memory effect occurs when the tested alloy is heated to the temperature below 320℃ ; when it is heated to the temperature between 320℃ and 450℃, the forward shape memory effect occurs; in the two stages, the shape of the sample remains the same as that in the furnace when it is taken out from the furnace and air-cooled; when the tested alloy is heated to the temperature above 450℃, the shape of the sample remains unchanged during heating, but the second reverse shape memory effect occurs after it is air-quenched.     

Ti-Ni-Cu形状记忆合金的温度记忆效应

采用差示扫描量热仪研究了Ti50Ni35Cu15以及Ti50Ni45Cu5(摩尔分数,%)形状记忆合金的温度记忆效应.结果表明:温度记忆效应仅在Ti-Ni-Cu合金的逆转变加热过程出现,在单斜结构马氏体与母相逆相变(B19'→B2)及正交结构马氏体与母相逆相变(B19→B2)过程中均能发生温度记忆效应;在随后的完全循环过程中,温度记忆记忆效应不再出现,DSC相变曲线又"恢复"到其原始形态;而在马氏体相变冷却过程中未发现温度记忆效应.分析表明,不完全相变过程中的弹性能再分布是可能的温度记忆效应机制.     

Surface morphology of sputtered NiTi-based shape memory alloy thin films

The effect of substrate condition and annealing treatment on the surface morphology of sputter-deposited NiTi-based thin films was studied by means of atomic force microscope. It is found that the surface of the film deposited at 450 °C on a (100) Si wafer is composed of large island groups, consisting of islands of 150–300 nm in diameter. Annealing treatment at 400 °C results in a more homogeneous distribution of the island size. However, for the film deposited at 450 °C on a (111) Si wafer, its surface consists of more homogeneous islands, being about 200–250 nm in diameter. For the film deposited at 450 °C on a SiO₂ buffer layer on top of the Si-substrate, the surface islands have ideal spherical shape. After annealed at 650 °C, the islands have grown to about 300 nm in width and 550 nm in length. The surface roughness of the deposited film is related not only to the island sizes but also to the island distributions.     

一种具有高形状回复率的双相 Ni-Mn-Ga-Gd 高温形状记忆合金

本文通过弯曲试验研究了双相Ni58Mn25Ga16.9Gd0.1合金的形状记忆效应和回复率。结果表明，该合金具有优异的形状回复能力。在预变形4.6%加热后，可以得到86%的形状回复率，高于已报道的双相Ni-Mn-Ga合金。这是因为Gd掺杂提高了γ 相的临界滑移应力，使γ 相不易发生变形。     

Factors affecting the generation of stress-assisted two-way memory effect in NiTi shape memory alloy

The combined effects of martensite pre-deformation and constrained stress on the generation of stress-assisted two-way memory effect (SATWME) were studied. Particular attention was paid to the generation of internal stress during thermal cycling under constant stress. The result highlights that the maximum SATWME is not determined solely by the maximum internal stress developed. The SATWME strain when subjected to 18% martensite pre-strain coincides, independently of constrained stress applied and internal stress developed. This study also provides experimental evidence that when under 400 MPa constrained stress the maximum SATWME shifts toward higher pre-deformation amplitude and this phenomenon is comparable to the increased cold-work. The results further suggest that the mechanism that associates with the change of M_s temperature plays critical role in determining the SATWME.     

Transformation hysteresis and shape memory effect of an ultrafine-grained TiNiNb shape memory alloy

In present work, transformation hysteresis and shape memory effect of an ultrafine-grained Ti₄₄Ni₄₇Nb₉ alloy processed by ECAP were studied. After deformation, the ECAPed sample showed a much wider transformation hysteresis than the initial sample due to the enlarged strength mismatch between matrix and β-Nb phase. The shape memory effect and its cycling stability of the ECAPed sample were obviously improved.     

A high-working-temperature CuAlMnZr shape memory alloy

The martensitic structure in the air-cooled Cu–11.91Al–2.48Mn–0.1Zr (wt%) alloy and its variation upon heating has been studied by X-ray diffraction and TEM. The forward and reverse thermoelastic transformation behavior has been studied by voltage measurement. The shape memory ratio of the alloy aged at 150 °C (in martensite state) for different times up to 100 h, or heated to different temperatures up to 620 °C followed by air cooling, has been measured. The air-cooled state of the alloy has a monoclinic martensitic structure M18R, which closely matches the N18R structure. This structure remains almost unchanged when the alloy is heated to 400 °C. When the alloy is heated to 620 °C, only a small amount of γ₂ phase precipitates and a shape memory ratio of 92% is achieved. When the alloy is aged at 150 °C for 100 h, a shape memory ratio of 97.2% is achieved.