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高志刚 《现代制造技术与装备》2007,(1):44-46
形状记忆合金是一种新型的功能材料,目前在许多领域都得到了应用。本文首先讨论了SMA材料的形状记忆原理,针对现行损伤模拟方法无法模拟结构损伤形成积累过程的不足之处,提出了将形状记忆合金SMA材料应用于损伤可控构件制作的方法,并介绍了形状记忆合金在机械、工程、电子以及医学领域的应用,并对前景作了分析。 相似文献
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铁基形状记忆合金管接头在油田管道连接中的应用 总被引:3,自引:0,他引:3
将铁基形状记忆合金管接头应用于油田防腐管道的连接、密封、堵漏,可避免管道内防腐层的破坏和焊接热影响区的腐蚀问题.介绍了铁基形状记忆合金管接头连接管道的基本原理,连接效果的影响因素,并对其进行了水压和拉拔试验,其密封性能、耐压性能和抗拉拔性均符合工程要求.现场连接试验表明,铁基形状记忆合金管接头用于油田防腐管道的连接可成功解决环氧粉末内喷涂钢管补口问题. 相似文献
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综述了形状记忆合金的发展概况,简要介绍了形状记忆合金在不同领域的应用现状,分析了当前形状记忆合金研究中存在的问题,指出了今后的发展前景与研究方向。 相似文献
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NiTi形状记忆合金因具有良好的形状记忆效应、超弹性、耐蚀性及生物相容性等被应用于生物医疗、航空航天及汽车等领域。激光焊接作为材料连接领域的重要技术之一,在NiTi形状记忆合金上的应用也受到了广泛关注。详细总结及分析国内外研究工作中关于NiTi形状记忆合金激光焊接接头的显微组织、力学性能、耐蚀性及生物相容性等方面的研究进展,同时分析如何提升NiTi形状记忆合金激光焊接质量的措施与机理。激光焊接过程中焊缝处镍元素的蒸发及热影响区内含镍金属间化合物的析出是导致焊接接头质量降低的根本原因,尽管通过工艺控制、焊缝合金化或焊后热处理等可提高焊接接头质量,但从目前结果来看仍有进一步提升的空间和需求。最后,结合现有研究进展及课题组的实际工作,给出NiTi形状记忆合金激光焊接未来可能的研究方向,旨在为后续的研究提供参考与借鉴。 相似文献
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形状记忆合金旋转驱动器结构设计方法 总被引:5,自引:2,他引:3
形状记忆合金是一种高效的驱动器.当使用形状记忆合金以较大的驱动力和驱动行程进行双向驱动时,需要增加偏置机构来完成对称动作.使用弹簧等作为偏置机构时,需要有持续能源输入维持变形.为克服这种缺陷,利用形状记忆合金单程记忆效应,以链轮链条传动机构作为依托,提出一种基于应变约束条件的旋转驱动器的结构设计方法.结构中以形状记忆合金作为无需能量输入的偏置机构,实现在单程记忆效应下的大行程双向驱动,并可消除链轮链条传动间隙.根据这种结构的特征,给出结构几何参数的设计公式及输出转矩公式,通过试验的方法研究旋转驱动器中形状记忆合金在应变约束条件下的应力应变特征,给出驱动过程中存在的应变死区,修正转角设计函数. 相似文献
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TiNi形状记忆合金与不锈钢钎焊接头的微观组织与性能 总被引:3,自引:0,他引:3
采用含Ag50%~68%、Cu10%~30%、Zn12%~20%、Sn0%~10%的银基钎料,通过激光钎焊,改变钎焊 有效热输入(激光输出功率和钎焊时间),研究了TiNi形状记忆合金与不锈钢异质钎焊接头的微观组织和性能。结 果表明:AgCuZnSn钎料对TiNi形状记忆合金和不锈钢的润湿性较好,钎焊接头界面平整、致密,与TiNi形状记 忆合金形成的界面反应层较窄,而与不锈钢形成的界面反应层较宽。钎焊有效热输入对TiNi形状记忆合金热影响 区组织和性能影响较大。钎焊有效热输入量过高,将导致TiNi形状记忆合金侧热影响区组织晶粒粗大、硬度降低、 塑性提高。严格控制钎焊工艺参数可以获得具有较高抗拉强度、形状记忆效应和超弹性的TiNi形状记忆合金与不 锈钢钎焊接头。 相似文献
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TiNi形状记忆合金/钛合金异种材料激光焊 总被引:1,自引:0,他引:1
由于TiNi合金与钛合金的物理和化学性能差异较大,故其焊接性较差,焊缝区易形成大量的金属间化合物并产生裂纹。为实现上述材料的良好连接、提高接头性能,本文对采用激光焊连接0.2mm厚TiNi形状记忆合金和TC4钛合金异种材料进行了探索。分别采用直接对接焊和手工填丝焊的方法,研究了焊接接头的微观组织和力学性能。结果表明,直接对接焊时焊缝中心产生了纵向裂纹;手工填丝焊则通过合适的焊接工艺,改善了焊缝成形,避免了裂纹的产生。较优的焊接工艺参数为功率百分比18%、脉冲宽度3ms、脉冲频率3Hz;在界面区,Ni与TC4形成的过渡层宽度约为2μm,Ni与TiNi形成的过渡层宽度约为0.5μm。接头最大抗拉强度为332MPa,断裂位置发生在靠近TiNi侧的熔合线附近。 相似文献
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The fretting behavior of superelastic nickel titanium (NiTi) shape memory alloy was studied at various displacement amplitudes on a serve-hydraulic dynamic test machine. The results showed that the superelastic properties of the material played a key role in the observed excellent fretting behavior of NiTi alloy. Due to the low phase transition stress (only 1/4 the value of its plastic yield stress) and the large recoverable phase transition strain (5%) of NiTi, the friction force of NiTi/GCr15 stainless steel pair is smaller than the value of GCr15/GCr15 pair and at the same time the Rabinowicz wear coefficient of NiTi plate is about 1/9 the value of GCr15 plate under the same fretting conditions. For NiTi/GCr15 pair, even NiTi has a much lower hardness than GCr15, the superelastic NiTi alloy exhibits superior fretting wear property than GCr15 steel. It was found that the weak ploughing was the main wear mechanism of NiTi alloy in the partial slip regime. While in the mixed regime and gross slip regime, the wear of NiTi was mainly caused by the abrasive wear of the GCr15 debris in the three-body wear mode. 相似文献
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In this paper, for the calculation of the deformation behaviors of shape-memory alloy under multi-axial loading conditions with temperature changes, a two-dimensional mechanical model of polycrystalline shape memory alloy is constructed on the bases of the crystal plasticity and the deformation mechanism of shape memory alloy. In such a model, the orientation of crystal grain in the polycrystal and the loading direction can be considered. The deformation behaviors under some complex loading conditions are calculated with the model, and the results show that they are in good qualitative agreement with the experimental results. 相似文献
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用磁悬浮熔炼、测定试样形状记忆效应(SME)、金相法、DSC、断口SEM和自由震动波衰减曲线等研究了高强度高塑性高阻尼的Mn基形状记忆合金的记忆特性,Cu、Ni、Fe、Cr、Ti、N等合金元素的作用。结果表明,Cu溶入愈多,合金的形状记忆效愈高;适当的时效热处理强化合金,提高SME;含Ti、N元素的合金Mn3有最好的SME,回复率达73%。所研究的合金都有明显的双程形状记忆效应,合金Mn3的双程形状记忆效应达21%,比较少见。淬火状态的合金有高的塑性,延伸率达25%,表示有极高的加工工艺性并有良好的阻尼抗震能力。淬火时效状态的合金有高的强度极限,尤其是高的屈服极限(σs=320—475MPa),适当的塑性(δ=4.2—5%以上),预示合金有较高的断裂韧性K1c,断裂前会有明显变形预示,提高构件工作安全性。合金元素还能提高所研究合金的抗氧化和抗腐蚀能力。 相似文献
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The limited length shrinkage of shape memory alloy (SMA) wire seriously limits the motion range of SMA-based gripper. In this paper, a new soft finger without silicone gel was designed based on pre bent SMA wire, and the finger was back to its original shape by heating SMA wire, rather than relying only on heat exchange with the environment. Through imitating palm movement, a structure with adjustable spacing between fingers was made using SMA spring and rigid spring. The hook structure design at the fingertip can form self-locking to further improve the load capacity of gripper. Through the long thin rod model, the relationship of the initial pre bent angle on the bending angle and output force of the finger was analyzed. The stress-strain model of SMA spring was established for the selection of rigid spring. Three grasping modes were proposed to adapt to the weight of the objects. Through the test of the gripper, it was proved that the gripper had large bending amplitude, bending force, and response rate. The design provides a new idea for the lightweight design and convenient design of soft gripper based on SMA. 相似文献