"形状记忆合金"专题序言

材料的形状记忆效应,最早可以追溯到1932年发现金镉合金的形状恢复现象;真正受到关注却是1963年美国海军实验室发明的NiTi合金。几年后该合金应用于"阿波罗"11号登月舱释放的直径数米的通讯天线。随后又在高分子、陶瓷等材料中发现了形状记忆效应。目前形状记忆材料已经成为重要的智能材料之一,在航空、航天、电子、机械、建筑、医学等领域取得了广泛应用。现已发现数十种形状记忆合金。按驱动方式,形状记忆合金可以分为温控和磁控两大类。     

热致型形状记忆高分子材料的研究进展

从记忆机理、制备技术等方面总结了热致型形状记忆高分子材料的最新发展并简述了当前几种重要的材料类型,特别是对近期发展的超分子形状记忆材料和可生物降解材料进行了重点描述,对未来热致型形状记忆高分子材料的发展方向进行了展望和评述.     

形状记忆高分子材料记忆行为机理的理论分析

形状记忆高分子材料(SMP)具有优良的形状记忆功能,是继形状记忆合金(SMA)之后的又一热点研究领域.形状记忆机理的理论分析在SMP的研发与应用过程中起着至关重要的作用,理论分析往往对实验研究起着指导性的作用.目前对于形状记忆高分子材料记忆行为机理的理论研究还比较少.本文综述自形状记忆高分子材料发现20多年以来众多学者在形状记忆机理的理论方面的进展,并且对于今后理论研究的方向提出一些见解.     

形状记忆材料的研究和应用

形状记忆材料是刺激响应性材料,能够利用外部的刺激改变它们的形状,包括形状记忆合金、形状记忆陶瓷、形状记忆聚合物三大类,主要介绍了形状记忆合金及聚合物的发展及其应用,并对它们的发展前景做出了展望。     

具有形状记忆特性的高分子聚合物

1.的形状记忆特性一提起形状记忆材料,立刻就会联想到金属,因为形状记忆合金已为人们所熟悉,它作为一种新材料正在进一步走向实用化。以塑料和橡胶为代表的高分子聚合物同形状记忆合金不一样,具有多种类型的形状     

日本金属新材料的标准化

所谓新材料,是指"通过物理性能、材料设计及加工、试验评价等阶段研究之后,确认其弥补了现有材料的缺陷,具有更优的特性、更强的功能、更好的结构、更高的附加值的材料"。新材料大体可分成金属、高分子和陶瓷等三个类别。随着高科技的发展,新材料不断涌现,如金属类的超耐热合金、形状记忆合金;高分子类的性能塑料、碳纤维补强塑料(CFRP);以及陶瓷类的精细陶瓷、光     

4D打印形状记忆高分子的打印方法、驱动原理、变形模式和应用

形状记忆高分子(Shape memory polymer,SMP)是指能够感知外界环境变化的刺激并响应这种变化,对其状态参数进行调整,从而回复到预先设定状态的一类高分子材料.相对于形状记忆合金和形状记忆陶瓷,SMP具有可回复形变量大、响应温度便于调节、刺激响应方式丰富、材料属性多样化、形状记忆效应种类多等优点,在医疗器械、柔性电子、纺织品、信息载体、航空航天以及软体机器人等领域展示了巨大的应用潜力.但SMP的原始形状或回复后的永久形状都较为单一,而且成型过程高度依赖模具并受脱模工艺的巨大限制,其形状难以制作得非常复杂,难以进一步满足新兴高科技领域对智能结构复杂性的需求.针对上述难题,国内外学者在该领域已进行了一些创新性的研究,当前的研究热点主要集中在以下两个方面:(1)在热固性高分子材料中引入动态共价键,通过交联网络结构重排实现固态塑性,进而对形状记忆材料的几何结构进行复杂化,这类形状记忆高分子材料也称为热适性形状记忆高分子;(2)利用3D打印(Three-dimensional printing)技术打印智能材料,实现材料几何结构的复杂化,并产生了一类新的打印技术,称为4D打印(Four-dimensional printing).其中,SMP材料是当前4D打印使用最多的智能材料.近年来,研究者以SMP材料为研究对象,结合最新的4D打印技术,采用熔融沉积成型、立体光刻成型、墨水直写和聚合物喷射技术制备了3D形状复杂的具有各种刺激响应方式和形状记忆效应的形状记忆材料.基于驱动原理不同,热、光、电、磁和水刺激响应形状记忆4D打印结构已经被成功设计和制备,丰富了具有复杂几何形状记忆材料的刺激响应类型;在变形模式上,实现了具有双形形状记忆效应、双向形状记忆效应、多重形状记忆效应和顺序梯度响应的4D打印形状记忆材料的设计、制备和应用.本文综述了4D打印SMP的打印方法、驱动原理、变形模式和应用,最后概述了4D打印SMP材料存在的问题及展望了其未来的发展方向.     

高分子形状记忆材料的研究进展

综述了近年来高分子形状记忆材料的研究进展,主要包括两个方面,(1)高分子形状记忆材料的制备;(2)高分子形状记忆材料的性能、配方及应用领域。     

热致感应型形状记忆高分子材料的研究EI

主要探讨了热致感应型形状记忆高分子材料的记忆机理，并对几种形状记忆高聚物的实施方法进行了研究和探讨，认为该类材料集塑料－橡胶的特性于一体，在记忆温度下的行为与橡胶的弹性理论相一致。     

形状记忆智能复合材料的发展与应用

智能材料是一种能够感知外部环境变化并自主进行判断、处理以及适度响应的新型智能多功能材料,同时也是继天然材料、合成高分子材料、人工设计材料之后的第四代材料,它的兴起引发了材料科学的一次新的革命。本文从形状记忆智能复合材料的历史起源入手,聚焦形状记忆合金和形状记忆聚合物最新研究成果,分别从形状记忆机理和工程实际应用等多个角度进行阐述,并对现阶段的技术发展难题,如形状记忆合金:生物相容性差、形变恢复小、驱动速度缓慢、疲劳寿命短;形状记忆聚合物:增材制造技术过程复杂、强度和刚度小等进行讨论,最后对未来发展前景进行展望。     

Shape-memory materials and hybrid composites for smart systems: Part I Shape-memory materials

A review is presented of the current research and development of shape-memory materials, including shape-memory alloys, shape-memory ceramics and shape-memory polymers. The shape-memory materials exhibit some novel performances, such as sensoring (thermal, stress or field), large-stroke actuation, high damping, adaptive responses, shape memory and superelasticity capability, which can be utilized in various engineering approaches to smart systems. Based on an extensive literature survey, the various shape-memory materials are outlined, with special attention to the recently developed or emerged materials. The basic phenomena in the materials, that is, the stimulus-induced phase transformations which result in the unique performance and govern the remarkable changes in properties of the materials, are systematically lineated. The remaining technical barriers, and the challenges to improve the present materials system and develop a new shape memory materials are discussed.     

Shape Memory Materials for Biomedical Applications

Shape memory properties provide a very attractive insight into materials science, opening unexplored horizons and giving access to unconventional functions in every material class (metals, polymers, and ceramics). In this regard, the biomedical field, forever in search of materials that display unconventional properties able to satisfy the severe specifications required by their implantation, is now showing great interest in shape memory materials, whose mechanical properties make them extremely attractive for many biomedical applications. However, their biocompatibility, particularly for long‐term and permanent applications, has not yet been fully established and is therefore the object of controversy. On the other hand, shape memory polymers (SMPs) show promise, although thus far, their biomedical applications have been limited to the exploration. This paper will first review the most common biomedical applications of shape memory alloys and SMPs and address their critical biocompatibility concerns. Finally, some engineering implications of their use as biomaterials will be examined.     

The recovery properties under load of a shape memory polymer composite material

In many applications, shape memory alloys are being replaced by shape memory polymers as they have some better properties than shape memory alloys. Nevertheless, shape memory alloys can recover under load which shape memory polymers cannot. Shape memory polymers are not capable of giving full recovery even lifting a tiny load. The melting temperature or the glass transition temperature is the transition temperatures to which shape memory polymers are closely heated. Then a deforming force up to a certain position is applied to the heated shape memory polymers. After that shape memory polymer is permitted to cool while keeping it deformed. After the cooling, shape memory polymer obtains the temporary shape which can be recovered by reheating it at the similar transition temperature (glass transition or melting). Consequently, it recovers at its initial state. Shape memory polymer can achieve constrained recovery and unconstrained recovery, nonetheless; under stress, it is partly recovered. In current work, recovery under load has been investigated of an asymmetrical shape memory composite. It is established that it is capable to recover under various loads. Under various loads, it shows full recovery in reference to initial state. The ability to recover under load can be potentially used in diverse applications.     

智能材料和结构

介绍了智能材料（intelloigent materials or smart materials)和智能结构（intelligent structure)的基本概念，分类和发展，并对当前材料研究关注热点的四类智能材料；压电陶瓷和压电聚合物，综合性光纤，形状记忆合金，电流变体和磁流变体作了较详细的描述，则时对智能材料和结构在各个领域中的应用进行了探讨。     

Corrosion degradation and prevention by surface modification of biometallic materials

Metals, in addition to ceramics and polymers, are important class of materials considered for replacement of non-functional parts in the body. Stainless steel 316, titanium and titanium alloys, Co-Cr, and nitinol shape memory alloys are the most frequently used metallic materials. These alloys are prone to corrosion in various extents. This review briefly discusses the important biomaterials, their properties, and the physiological environment to which these materials are exposed. Corrosion performance of currently used metallic materials has been assessed and threat to the biocompatibility from corrosion products/metal ions is discussed. The possible preventive measures to improve corrosion resistance by surface modification and to increase the bioactivity of the metallic surfaces have also been discussed. Importance of the formation of oxide layers on the metal surface, another aspect of corrosion process, has been correlated with the host response. The gap areas and future direction of research are also outlined in the paper.     

形状记忆高分子材料的研究进展

本文就形状记忆高分子材料的研究现状进行了概述，在形状记忆原理的基础上，着重讨论了聚降冰片烯、反式聚异戊二烯，苯乙烯－丁二烯共聚物和聚氨酯等形状记忆高分子的特性及其应用，并指出了它们的发展前景。     

Recent advances in shape memory polymers and composites: a review

Shape memory polymers (SMPs) belong to a class of smart polymers, which have drawn considerable research interest in last few years because of their applications in microelectromechanical systems, actuators, for self healing and health monitoring purposes, and in biomedical devices. Like in other fields of applications, SMP materials have been proved to be suitable substitutes to metallic ones because of their flexibility, biocompatibility and wide scope of modifications. The shape memory properties of SMPs polymers might surpass those of shape memory metallic alloys (SMAs). In addition to block copolymers, polymers blends and interpenetrating network structured SMP systems have been developed. The present review mainly highlights the recent progress in synthesis, characterization, evaluation, and proposed applications of SMPs and related composites.     

A review of shape memory polymer composites and blends

Shape memory polymers (SMPs) are a kind of very important smart polymers. In order to improve the properties or obtain new functions of SMPs, SMP composites and blends are prepared. We thoroughly examine the research in SMP composites and blends achieved by numerous research groups around the world. The preparation of SMPs composites and blends is mainly for five aims: (1) to improve shape recovery stress and mechanical properties; (2) to decrease shape recovery induction time by increasing thermal conductivity; (3) to create new polymer/polymer blends with shape-memory effect (SME); (4) to tune switch temperature, mechanical properties, and biomedical properties of SMPs; (5) to fabricate shape memory materials sensitive to electricity, magnetic, light and moisture. The trend of SMP composite development is discussed. SMP composites and blends exhibit novel properties that are different from the conventional SMPs and thus can be utilized in various applications.     

Perspective in Development of Shape Memory Materials Associated with Martensitic Transformation

By consideration of the characteristics of martensitic transformation and the derivation from the application of the group theory to martensitic transformation, it may be concluded that the shape memory effect (SME) can be attained in materials through a martensitic transformation and its reverse transformation. only when there forms single or nearly single variant of martensite, with an absence of the factors causing the generation of the resistance against SME. on this principle, various shape memory materials including nonferrous alloys. iron-based alloys and ceramics containjng zirconia are expected to be further developed. A criterion for thermoelastic martensitic transformation is presented, Factors which may act as the resistance against SME in various materials are briefly described     

TiNi形状记忆合金连接技术的研究进展

TiNi形状记忆合金具有很多优异性能,在航空航天、原子能、海洋开发、仪器仪表以及医疗器械等领域具有广阔的应用前景,而TiNi形状记忆合金的连接技术是其实用化的关键技术之一.综述了TiNi形状记忆合金连接技术的发展现状,重点评述了TiNi形状记忆合金激光焊、固相焊和钎焊的研究状况,指出了需要深入研究的问题.