Fe—Mn—Si基形状记忆合金及其应用

介绍了形状记忆合金的简要发展史,Fe-Mn-Si合金的形状记忆机理以及合金的主要元素组成,各成分的作用,提高记忆的方法,分析了其应用情况和前景。     

Fe－Mn－Si形状记忆合金研究进展

对近年来Ｆｅ－Ｍｎ－Ｓｉ合金形状记忆效应的影响因素及工程应用的研究结果进行了评述，并对Ｍｎ、Ｓｉ元素，母相强化及热－机械训练对记忆效应的影响进行了讨论     

Fe-Mn-Si形状记忆合金的记忆性能分析

铁基形状记忆合金由于具有优良的形状记忆效应、价格低廉以及加工性能好等优点引起了广泛重视。对Fe-Mn-Si形状记忆合金的形状记忆机制、形状记忆效应的影响因素以及应用进行了评述。     

Damping performance of Cu-Zn-Al shape memory alloys in engineering structures

The stress strain curves of two CuZnAI shape memory alloys which have the martensltic transformation temperatures of 50℃ and-10℃ respectively, were measured by using electronic material tester after treated by different heat-treatment conditions. The results show that the area enclosed by hysteresis loop of the CuZnAI shape memory alloy in martensltic state is much larger than that of the alloy in austenltic state with super-elasticity at room temperature. Therefore, the former has better vibration attenuation effect. After being oil-quenched, waterquenched, and step-quenched, the CuZnAI alloy takes on more stable shape memory effect, better super-plasticlty and superelasticity (pseudoelasticity). A CuZnAI shape memory alloy damper was designed, produced and installedto a 2-layer frame structure. In addition, the vibration experiments were made by dynamic data collecting analysis meter. The velocity of vibration attenuation of frame structure with CuZnAI shape memory alloy damper is much faster than that without it. And with the help of CuZnAI shape memory alloy damper, the attenuation period reduces to 1/10 of the original.     

Effect of impact deformation on shape recovery behavior in Fe-Mn-Si shape memory alloy under shape memory training process with cyclic thermo-mechanical loading

In the past studies, it has been discovered that the shape memory effect(SME) in the Fe-Mn-Si shape memory alloy(Fe-SMA)can gradually be enhanced by a pre-process called as shape memory training process under cyclic thermo-mechanical loading.On the other hand, it has been shown that the SME of Fe-SMA can also be affected by changing the strain rate. Therefore, it is possible to improve the SME by combining the strain rate sensitivity and shape memory training process. However, the improvement of SME caused by the training process under impact condition is still unclear. For the training process under impact condition, it is difficult to interrupt the test at the desired strain level due to many reflections of stress waves, which reload the specimen from the free ends. In this paper, to obtain reliable experimental results of SME after the training process under impact condition, the stress waves after first loading are eliminated by the double momentum-trap structure introduced into the impact tensile testing apparatus based on the split Hopkinson pressure bar method. In order to achieve an optimum design of the structure used in experiments, the finite element simulation of the structure is performed. Then, tensile tests in the training process of Fe-28Mn-6Si-5Cr alloy at different strain rates including the impact level are conducted and temperature change of the specimen is measured during training and heating process. As a result, the improvement of SME in the alloy after the training process under quasi-static and impact loading is compared with that under quasi-static loading through verification processes.     

Phase transformation behaviors and shape memory effects of TiNiFeAl shape memory alloys

Measurements of electrical resistivity, X-ray diffraction, and tensile test at room temperature and ?196°C were performed to investigate the effects of Al addition substituting Ni on the phase transformation behaviors, the mechanical properties, and the shape memory effects of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys. It is found that 1at% Al addition dramatically decreases the martensitic start transformation temperature and expands the transformation temperature range of R-phase for TiNiFeAl alloys. The results of tensile test indicate that 1at% Al improves the yield strength of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys by 40% and 64%, but de- creases the plasticity to 11% and 12% from 26% and 27% respectively. Moreover, excellent shape memory effect of 6.6% and 7.5% were found in Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys, which results from the stress-induced martensite transformation from the R-phase.     

Fe-Mn-Si形状记忆合金的记忆性能分析

铁基形状记忆合金由于具有优良的形状记忆效应、价格低廉以及加工性能好等优点引起了广泛重视。对Fe-Mn-Si形状记忆合金的形状记忆机制、形状记忆效应的影响因素以及应用进行了评述。     

双程形状记忆效应的唯象动力学模型

构造可以用于描述一维结构的形状记忆合金（SMA）的双程形状记忆效应的唯象动力学模型. 该模型基于与形状记忆合金中热弹性相变有关的唯象理论,将应力场和热场下的滞回环曲线视为马氏体相变和马氏体变体重构在宏观层面上的表现. 为了模拟温度诱发的相变,构造非凸自由能函数,使得函数的每个局部平衡对应于相变过程中的一个相. 在外部负载（力或者热）的作用下,可以通过模拟系统状态（应变）在不同平衡态之间的转变,研究温度诱发的相变. 相变动力学的控制方程采用拉格朗日方程,以非线性微分方程来表示. 利用非线性常微分方程描述单程形状记忆效应,通过对不同相变过程的加权组合描述双程形状记忆效应. 开展有关力和热负载下的数值实验,模拟热和应力诱发的相变以及热负载下与单程形状记忆效应和双程形状记忆效应有关的滞回环,模拟马氏体重构所导致的单滞回环以及超弹性效应所引起的双滞回环. 从实验结果可以看出,双程形状记忆效应及超弹性效应均可以被提出的模型成功捕捉,验证了该模型的描述能力.     

The Deformation Behavior of TiNi Shape Memory Alloy under Axial Dynamic Compression

The deformation behavior of Ti-50.9at% Ni shape memory alloy under axial compression dynamic loads was investigated by an MTS 858Miru Bionic test machine. The alloy were aged at 500℃ for an hour before being machined into specimens. The compression experiments were conducted at 20℃ and the variety of dynomic loads were controlled by the strain rate, which was 3mm/min, 15mm/min, 30mm/min and 50mm/min, respectively. The experimental results indicate that in the case of 3mm/min. stress-induced martensitic transformation occurs at about 350 MPa when loading and reverse transformation at about 200 MPa when unloading, during which the aged Ti-50.9at% Ni alloy shows the recoverable nonlinear pseudoelastic strain of 4.3%with the residual strain of 1.2% reserved. With the strain rate increasing, the area encloses by loading-curve and unloading-curve, i. e stress ( strain ) hysteresis becomes smaller and smaller and the residual strain also decreases, while critical stress for inducing martensitic transformation rises. At a higher strain rate the alloy exhibits linear-like pseudoelasticity, which is up to 4.5％ .     

Microstructure and shape memory effect of Cu-26.1Zn-4.8Al alloy

The influence of processing parameters on the microstructure and shape memory effect of Cu-26.1Zn-4.8Al alloy was investigated. The treated specimens were characterized by metallography, X-ray diffraction （XRD） and transmission electron microscopy （TEM） to explain the mechanism of shape memory effect in Cu-26.1Zn-4.8Al alloy. The results reveal that the shape memory effect is markedly increased by appropriate quenching and ageing process. XRD shows that γ phase precipitates from martensite when aged at higher temperature and γ precipitates impair the shape memory effect. TEM analysis indicate that the substructure of plate-like martensite consists of twins and stacking faults.     

NiTi形状记忆合金应变传感特性分析

阐述了形状记忆合金丝的应变传感原理.在Brinson建立的形状记忆合金一维本构模型的基础上,引入Ikuta提出的电阻率与马氏体百分含量之间的关系并对其进行简化,建立了形状记忆合金应变传感特性的理论分析模型.分析了不同温度条件、不同初始状态的形状记忆合金电阻相对变化率与应变之间的关系.并与已有试验结果进行比较,验证了该模型的有效性.结果表明,形状记忆合金可以作为应变传感元件使用,温度对形状记忆合金的传感特性有影响,设计时要根据使用温度来确定形状记忆合金的相变温度.     

电场作用下HAP/NiTi形状记忆合金复合材料制备工艺研究

为改善NiTi形状记忆合金的耐蚀性和生物相容性,利用外加交变电场的作用在合金表面沉积羟基磷灰石(HAP)涂层,从而制得HAP/NiTi形状记忆合金复合材料.实验探讨了交变电场的电压、频率和作用时间对NiTi形状记忆合金表面沉积羟基磷灰石涂层的影响.结果表明:随着电场电压、电流频率和作用时间的增加,NiTi合金表面钙磷涂层的厚度逐渐增加,组织变得均匀致密,但若频率过大,时间过长则涂层反而被破坏,故确定最佳电场作用参数为300V+20Hz+5h.涂层呈疏松多孔的羽针状结构,经XRD检测其组织主要为羟基磷灰石,且在模拟体液中具有较好的生物稳定性.     

聚乙二醇基形状记忆水性聚氨酯的合成与性能研究

用不同相对分子质量的聚乙二醇(PEG)为软段,以IPDI-BDO-DMPA为硬段,合成出一系列含有可结晶软段的水性聚氨酯材料,并通过红外、DSC以及形状记忆性能测试等手段对样品的软段结晶性和形状记忆功能进行表征.结果表明:软段相对分子质量、硬段含量都对软段的结晶性有很大的影响;只有PEG相对分子质量大于2 000时合成的聚氨酯的软段才具有结晶性,并且软段的熔融温度和熔融焓会随着PEG相对分子质量的增大而增大;若软段的相对分子质量一定,则样品的熔融温度和熔融焓会随着硬段含量的增加而呈现减小的趋势;当软段为PEG 4 000、硬段质量分数为30%时,该材料表现出良好的形状记忆性能.     

形状记忆合金混杂复合材料弯曲变形的研究

为精确地预报形状记忆合金混杂复合材料的弯曲变形量及在不改变构件刚度的条件下增大其弯曲变形量,对该材料悬臂梁的弯曲变形进行了研究．采用板状形状记忆合金增大形状记忆合金的体积分数;通过测试形状记忆合金关键温度点上的回复应力与弹性模量,确定形状记忆合金本构方程中的有关变量,解本构方程获得各个温度下的回复应力与弹性模量．采用有限元方法进行计算,获得了悬臂梁弯曲变形的温度响应曲线．测试实验验证了计算的正确性．     

Microstructure,martensitic transformation and shape memory effect of polycrystalline Cu-Al-Mn-Fe alloys

In this study, two Cu-Al-Mn-Fe polycrystalline alloys were prepared, and their microstructure, reversible martensitic transformation, mechanical properties and shape memory effects were investigated. The results show that the reversible martensitic transformation temperatures of the studied alloys are between room temperature and 373 K, which are suitable for practical applications. Two typed martensites of 18R and 2H coexist both in two alloys. The bcc β(FeAl) nanoparticles are Fe-rich, Mnrich and Cu-poor, whereas the martensite is Cu-rich, Fe-poor and Mn-poor. The size of nanoparticles ranges from tens to hundreds of nanometers. Full shape recovery property is displayed in Cu-12.9Al-4.5Mn-2.6Fe alloy all the time while applying different deformation from 5% to 8%. The maximum recoverable strain is up to 4.4% with a recovery rate of 100%.     

Cu—Zn—AL记忆合金的热稳定性

本文研究了Cu—Zn—Al形状记忆合金在加热过程中的稳定性。实验结果表明:Cu—Zn—Al合金记忆效应的实际使用温度决定于该合金的贝氏体转变温度,合金中的贝氏体相变至少在长大阶段是扩散控制的。Cu—Zn—Al合金中Mn元素的加入使合金中的扩散能较快地进行,因而降低了合金记忆效应的热稳定性。     

形状记忆合金对混凝土梁驱动效应的有限元分析

将常温下为马氏体状态的Ni—Ti形状记忆合金预拉伸到产生塑性变形后，再把其偏心埋置于钢筋混凝土梁中，利用SMA特殊的形状记忆效应，通过加热合金丝使其发生马氏体逆相变从而产生巨大的恢复力来驱动钢筋混凝土梁。本文运用通用有限元计算软件ANSYS进行了建模和分析，结果证明可以利用SMA对混凝土梁施加较大的预应力，提高梁的强度和刚度．从而实现变形的主动控制，     

Martensitic stabilization and defects induced by deformation in TiNi shape memory alloys

Martensitic stabilization caused by deformation in a TiNi shape memory alloy was studied.Special attention was paid to the deformed microstructures to identify the cause of martensitic stabilization.Martensitic stabilization was demonstrated by differential scanning calorimetry for the tensioned TiNi shape memory alloy.Transmission electron microscopy revealed that antiphase boundaries were formed because of the fourfold dissociation of [110]B19' super lattice dislocations and were preserved after reverse t...     

Low Velocity Impact Response Analysis of Shape Memory Alloy Reinforced Composite Beam

The low velocity impact responses of shape memory alloy （ SMA ） reinforced composite beams were analyzed by employing the finite element method. The finite element dynamic equntion was solved by the Newmark direct integration method, the impact contact force was determined asing the Hertzian contact law, and the influence of SMA .fibers on stiffiwss matrix is studied. Numerical results show that the SMA fibers can effectively improve the low velocity impact response property of composite beam.     

偏动式形状记忆合金驱动器系统建模与仿真

为了实现响应速度快、精度高的偏动式形状记忆合金驱动器控制系统,基于Kanaka-Liang提出的形状记忆合金材料一维本构关系建立了偏动式SMA驱动器的热动力学模型.针对形状记忆合金材料的非线性迟滞特性,结合PID控制和模糊控制各自的优点,设计了一种模糊增益自调整PID复合控制器方案,并对偏动式形状记忆合金驱动器的响应特性进行了仿真.仿真结果表明,与PID控制器和模糊控制器相比,模糊增益自调整PID复合控制器具有响应快、超调小、适应性好等优点.模糊增益自调整PID控制策略完全能满足偏动式形状记忆合金驱动器对控制精度的要求.