共查询到18条相似文献,搜索用时 102 毫秒
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用拉伸实验研究了Fe-15.2Mn-6Si-8.3Cr-7Ni、Fe-16Mn-5Si-9Cr-4Ni和317L不锈钢的应力应变曲线。结果表明,铁基形状记忆合金存在显著的超弹性。其应力应变曲线上,卸载时的曲线和再加载时的曲线相比有明显的滞后。合金卸载时存在极大的非线性回弹εsb,εsb随变形量的增加而增加,而超弹性应变εSE在小变形量下随变形量的增加而增加,当总变形量超过一定值时,εSE不再增加。Fe-15.2Mn-6Si-8.3Cr-7Ni的最大超弹性应变εSE可达到0.75%。应力诱发马氏体与母相之间界面移动产生超弹性,超弹性受化学驱劝力和母相对马氏体相的弹性约束控制。热形成马氏体和母相强度对超弹性影响不大。 相似文献
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Fe—Mn—Si—Cr—Ni形状记忆合金超弹性的研究 总被引:2,自引:0,他引:2
用拉伸实验研究了Fe-15.2Mn-6Si-8.3Cr-7Ni、Fe-16Mn-5Si-9Cr-4Ni和317L不锈钢的应力应谜面工线。结果表明,铁基形状记忆合金存在显著的超弹必 相似文献
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对超弹性形状记忆合金(SMA)丝在不同应变幅值和荷载速率下进行加卸载单轴拉伸试验,分析其滞回特性随环境因素的变化规律。将径向基函数神经网络(RBFNN)和Graesser模型结合起来,Graesser模型参数取自试验曲线,能由数学式确定的模型参数和应变幅值、荷载速率一起作为网络的输入信息,不能由数学式确定的模型参数作为输出神经元。数值计算表明,RBFNN可以精确地预测Graesser模型参数,且计算的SMA应力-应变曲线与Graesser模型结果吻合很好。 相似文献
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为了在常温条件下更充分地利用TiNi形状记忆合金绞线的超弹性性能,以Ti-50.75%(原子分数)Ni形状记忆合金(SMA)丝和绞线两种形式试件进行了室温条件下,加载速率、应变幅值及循环次数等因素对SMA丝和SMA绞线超弹性性能影响的试验。试验表明SMA以绞线的形式使用时能够大幅度提高其极限应变能力,相对SMA丝来说更适合应用于大变形时提供足够的恢复力;SMA绞线相对SMA丝具有更强大的超弹性性能;SMA绞线的残余应变量要比SMA丝的小得多,这也是使它具有较高的超弹性性能的主要因素之一.从而验证了SMA以绞线形式使用可以提供更强的超弹性性能. 相似文献
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Nickel-Titanium alloys with stoichiometric single phase and non-stoichiometric dual phase structures of NiTi and NiTi+Ni3Ti are produced through high speed induction melting and combustion synthesis of pure Ti/Ni elements. Both alloys are homogenized at 1273 K for two hours, rolled into thin strips of 0.3 mm thickness, solution treated at 1273 K for two hours under vacuum and finally quenched in water. Effect of ageing on austenite/martensite and intermediate phase transformation temperatures are investigated. Results show that transformation temperatures and reversible shape memory properties comparable with those required for bioengineering applications such as manufacturing of artificial hand prostheses can be obtained through careful control of the chemical composition and the heating processes. 相似文献
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CuZnAlMnNi形状记忆合金马氏体相变焓的研究 总被引:2,自引:0,他引:2
采用差示扫描量热分析技术在5℃/min以及在超低降温速率下,研究了CuZnAlMnNi形状记忆合金马氏体相变的热焓。通过实验和计算,由母相向马氏体转变时单位质量的相变总焓、热容改变焓和马氏体相变焓分别是3.22J/g、1.88J/g和1.34J/g。 相似文献
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Effects of Heat Treatment on the Transformation Temperature and the Microstructure of Ni-Ti-Nb Shape Memory Alloy 总被引:1,自引:0,他引:1
The effects of heat treatment on the phase transformation temperature and the microstructure of Ni-Ti-Nb alloy have been investigated by means of R-T method, TEM and EPMA. With the increase of annealing temperature, cooling rate and ageing temperature, the Ms temperature increases. TEM observations show no new precipitated phase was found in the B2 parent phase after heat treatment, but EPMA shows the content of Ni (or Ni/Ti ratio) in the B2 matrix changed. The main reason for the change of transformation temperature lies in the change of the matrix composition (or Ni/Ti ratio) with the variation of heat treatment procedure. 相似文献
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This work investigates the evolution of effective phase transformation thresholds in superelastic shape memory alloy (SMA) lattice architectures subjected to cyclic loading. The investigation is carried out by means of finite element analysis and numerical homogenization methods, considering Schwarz primitive triply periodic minimal surface (TPMS) SMA unit cells subjected to periodic boundary conditions. The results are reported for relative densities between 10% and 50%. It is shown that, in all the cases considered, the loading surfaces governing both forward and reverse phase transformations have an ellipsoidal shape that can be reasonably well represented using an extended Hill's criterion that accounts for the influence of hydrostatic pressure. Moreover, by considering polynomial expressions of the coefficients of Hill's criterion in terms of martensite volume fraction and cumulated fraction, the evolution of the loading surfaces as a consequence of functional fatigue is reasonably well approximated. The results suggest that an extended Hill's criterion with variable coefficients can well be used to simulate effective phase transformation and functional fatigue in architected TPMS SMAs. 相似文献
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TiNi形状记忆合金阻尼特性的研究 总被引:6,自引:1,他引:6
在变频、变温条件下,对两种热处理方式处理的Ti-50.8Ni(原子分数,%)合金的低频阻尼特性进行了研究,结果表明:中温退火处理的Ti-50.8Ni合金的阻尼性能好于高温固溶时效处理的合金;马氏体相、R相阻尼高于母相阻尼,相变过程(多相共存)出现阻尼峰,远远高于母相、马氏体相阻尼,同时伴随有最小弹性模量峰,即相变时材料出现软化现象;相变时阻尼与频率成反比,频率越高,相变阻尼峰越不明显,频率对弹性模量变化几乎没有影响;相变结束合金的阻尼对温度及频率不敏感;中温退火处理的Ti-50.8Ni合金在降温过程中由于温度和应力的复合作用导致多次相变,出现受频率影响的多个相变阻尼峰。 相似文献