1995年世界钛工业的回顾与展望

采用Ｘ射线衍射及ＴＥＭ技术研究了Ｔｉ４４Ｎｉ４７Ｎｂ９形状记忆合金的相组成及热诱发马氏体相变。结果表明：该合金室温下由ＴｉＮＩ基体相和β－Ｎｂ相组成；当试样温度降低到Ｍｓ点以下时，具有Ｂ１９＇单斜结构的热诱发马氏体呈群团状区域式生长，形成由２－３个取向的孪晶微区组成的群团状马氏体；马氏体的亚结构主要为（１１１）ＭⅠ型孪晶，同时还有（００１）Ｍ孪晶和反相畴界。     

含钌钛合金及其性能和应用

应用扫描电镜、电子探针、Ｘ射线衍射、低温拉伸及电阻法等分析技术，研究了５种Ｔｉ－Ｎｉ－Ｎｂ形状记忆合金的组织、相变特性和应变恢复率。结果表明：随着Ｔｉ－Ｎｉ－Ｎｂ合金中铌含量的增加。β－Ｎｂ相的体积分数增加，Ｍｓ温度和应变恢复率降低，而相变温度滞后变化不大。为获得较宽的相变温度滞后和高的应变恢复率，Ｔｉ－Ｎｉ－Ｎｂ合金的铌含量应控制在８ａｔ％￣９ａｔ％之间。     

Ni47Ti44Nb9合金中各相的低温热容

采用精密自动绝热量热装置测定了Ｎｉ４７Ｔｉ４４Ｎｂ９和Ｎｂ８０Ｔｉ１４Ｎｉ６合金６０～３５０Ｋ温区的热容，并将热容实测值用最小二乘法进行了曲线拟合。在合金摩尔热容加和原则基础上，计算了Ｎｉ４７Ｔｉ４４Ｎｂ９合金中ＴｉＮｉ基体相的热容。Ｎｉ４７Ｔｉ４４Ｎｂ９合金在２１５～２６０Ｋ范围内发生的相变是ＴｉＮｉ相的热弹性马氏体相变。相变起始温度（Ａｓ）为２２２Ｋ，相变终了温度（Ａｆ）为２５５Ｋ，相变焓ΔＨ＝４１１．９±２．５Ｊｍｏｌ－１，相变熵ΔＳ＝１．７６±０．０１ＪＫ－１ｍｏｌ－１     

合金成分对Ti－Ni－Nb合金相变特性及形状记忆效应的影响

应用扫描电镜、电子探针、Ｘ射线衍射、低温拉伸及电阻法等分析技术，研究了５种Ｔｉ－Ｎｉ－Ｎｂ形状记忆合金的组织、相变特性和应变恢复率。结果表明：随着Ｔｉ－Ｎｉ－Ｎｂ合金中铌含量的增加，β─Ｎｂ相的体积分数增加，Ｍ＿ｓ温度和应变恢复率降低，而相变温度滞后变化不大。为获得较宽的相变温度滞后和高的应变恢复率，Ｔｉ－Ｎｉ－Ｎｂ合金的钥含量应控制在８ａｔ％～９ａｔ％之间。     

Ti—Ni—Nb宽滞后记忆合金的研究进展

Ｔｉ－Ｎｉ－Ｎｂ形状记忆合金由于其较宽的相变滞后和优良的形状记忆性能,是一眼有前任的管接头和紧固件用材。本文论述了Ｔｉ－Ｎｉ－Ｎｂ合金滞后加宽的工程意义,介绍了近十年来Ｔｉ－Ｎｉ－Ｎｂ合金显微组织,马氏体相变,力学行为,应变恢复率,低温热容和机械加工特性等方面的研究进展及发展趋势。     

1Cr18Ni9Ti不锈钢形变诱发马氏体相变规律及其对孔敏感性…

通过低温（－７０℃）拉伸制备不同马氏体相变量１Ｃｒ１８Ｎｉ９Ｔｉ试样，用ＸＲＤ，ＴＥＭ及金相观察研究形变诱发马氏体相变的规律。用电化学方法研究α马氏体（铁磁相）含量对１Ｃｒ１８Ｎｉ９Ｔｉ钢在含Ｃｌ＾－溶液中孔蚀敏感性的影响，结果表明，随试样变形量加大，形变诱发马氏体中铁磁性的α马氏体含量不断增大，而ε马氏体相的量始终较小。材料的孔蚀敏感性失随铁磁相含量的增大而增大，当铁磁相含量达到４．５８％以后，     

Ti—47Al—2Mn—2Nb合金低温静态和动态拉伸性能及硼的影响

采用常规拉伸和Ｈｏｐｋｉｎｓｏｎ拉杆技术,研究具有近全片层组织形变Ｔｉ－４７Ａｌ－２Ｍｎ－２Ｎｂ合金１８０Ｋ下静态和动态拉伸性能及其受硼的影响。发现Ｔｉ－４７Ａｌ－２Ｍｎ－２Ｎｂ和Ｔｉ－４７Ａｌ－２Ｍｎ－２Ｎｂ－１Ｂ合金１８０Ｋ下的拉伸强度均比室温度。     

Cu-Al-Mn-Zn-Zr记忆合金的应力诱发马氏体相变及其逆转变

利用拉伸实验、电阻－温度曲线测量、X射线衍射、金相与透射电镜观察等方法研究了Cu-18.4Al-8.7Mn-3.4Zn-0.1Zr(原子分数，％）合金应力诱发马氏体的稳定性与可逆性。结果表明，顺Ms以上变形，实验合金发生应力诱发β1→M18R转变，但应力诱发马氏体转变很难进行完全。当变形量高达7．5％时，仍存在未发生应力诱发转变的母相。应力诱发马氏体的稳定性和可逆性与变形量大小有关，合金经大变形量变形后，即使在250℃油浴中回复，仍存在未发生逆变的应力诱发马氏体。在一定的变形条件下，经适量变形的应力诱发马氏体具有很高的可逆性和稳定性，实验合金在Ms以上10－50℃温度范围内变形6．5％－9．0％时，相变滞后宽度可达90℃以上，记忆应变＞3．5％。     

Ti-Ni-Nb宽滞后形状记忆合金的应力诱发马氏体相变行为

用在（Ms＋30℃）温度下的拉伸实验和差示扫描量热仪（DSC）较系统地研究了Ti44Ni47Nb9宽滞后形状记忆合金应力诱发马氏体的相变行为。研究结果表明：当形变量达到14％左右时，应力诱发马氏体相变过程基本完成。应力诱发马氏体的逆相变温度间隔要比热诱发马氏体约小一个数量级。形变对该合金应力诱发马氏体的逆转变开始温度、逆转变温度间隔以及相变潜热均有明显影响，随着拉伸变形量的增加而增加。而在随后的冷却循环中，相变潜热和马氏体相变开始温度均随着形变的增加缓慢降低。     

Fe—5Ni合金奥氏体高温变形行为

在温度９７３－１３７３Ｋ，形变速率２×１０＾－５－１．５×１０＾－２ｓ＾－１的试验条件下，研究了Ｆｅ－５Ｎｉ合金奥氏体的高温拉伸变形行为。结果表明：高温变形时峰值应力σｐ与温度Ｔ和形变ε之间符合五式关系：Ｚ＝εｅｘｐ（Ｑ／ＲＴ）＝Ａ（ｓｉｎｈ（ασｐ））＾ｍ。高应变速率区的激活能Ｑ为３１４ｋＪ／ｍｏｌ，与Ｆｅ的自扩散激活能Ｑｓｄ相当，变形由空位扩散所控制；而低应变速率区的Ｑ为２０２ｋＪ／ｍｏｌ，约     

形变温度对FeMnSiCrNiC合金第二相方向性析出及记忆效应的影响

基于控制第二相方向性析出提高铁基合金形状记忆效应的构想,研究了不同形变温度对Fe13.53Mn4.86Si8.16Cr3.82Ni0.16C合金γ/ε界面(母相丫与诱发马氏体ε之间界面)的数量和结构及随后时效第二相析出的数量和方向性的影响,以及第二相析出的数量和方向性对马氏体相变和形状记忆效应的影响.扫描电镜分析显示,形变温度远高于Ms时,无γ/ε面产生,时效后第二相析出少;形变温度接近Ms时,产生大量γ/ε面,时效后析出第二相数量很多,且方向性良好;形变温度进一步接近Ms时,γ/ε界面交叉,导致时效后方向性的第二相也交叉.透射电镜分析显示,析出方向性Cr23C6第二相的合金再次进行预变形时,产生的应力诱发马氏体具有单一方向.原因在于方向性Cr23C6及其产生的应力场对马氏体相交产生约束作用,避免马氏体片之间的交叉,使其具有更好的可逆转变性.     

Stress-induced martensitic transformation in （Ni47Ti44）100-xNbx shape memory alloys with wide hysteresis

The effect of deformation via stress-induced martensitic transformation on the reverse transformation behavior of the （Ni47Ti44）100-xNbx （x=3, 9, 15, 20, 30, mole fraction, %） shape memory alloys was investigated in detail by differential scanning calorimetry （DSC） after performing cryogenic tensile tests at a temperature of Ms＋30 ℃. The results show that Nb-content has obvious effect on the process of stress-induced martensitic transformation. It is also observed that the stress-induced martensite is stabilized relative to the thermally-induced martensite （TIM） formed on cooling, and Nb-content in Ni-Ti-Nb alloy has great influence on the reverse transformation start temperature and transformation temperature hysteresis of stress-induced martensite（SIM）. The mechanism of wide transformation temperature hysteresis was fully explained based on the microscopic structure and the distribution of the elastic strain energy of （Ni47Ti44）100-xNbx alloys.     

热诱发ε马氏体量对Co-30Ni合金形状记忆效应的影响

为了明确具有ε马氏体转变的Co-Ni基合金形状记忆效应的来源,通过控制不同变形温度,在Co-30Ni合金中获得不同数量的热诱发ε马氏体,在此基础上利用OM和XRD研究了变形时预先存在的热诱发ε马氏体的演化及其对应力诱发ε马氏体转变的影响,并采用弯曲法表征了合金的形状记忆效应。结果表明:合金的形状记忆效应都随热诱发和应力诱发ε马氏体数量的增加而升高,但原位金相未观察到热诱发ε马氏体在应力下的长大合并。Co-Ni基合金的形状记忆效应来源于应力诱发ε马氏体转变,而不是热诱发ε马氏体在应力下的长大合并。低的母相屈服强度是Co-Ni合金形状记忆效应差的原因。预先形成的热诱发ε马氏体能提高母相的屈服强度,因而有利于形状记忆效应的提高。     

两种不同变形方式对NiTi合金回复特性的影响

研究了马氏体再取向(MR)和应力诱发马氏体转变(SIM)两种不同变形方式对Ni50.2Ti49.8合金拉伸性能及预应变后加热回复特性的影响.结果表明:拉伸变形中,MR变形方式的应力平台结束时的应变值较SIM变形方式大.在拉伸预应变处于应力平台阶段时,两种变形方式在相同预应变后加热回复有相同的记忆能力;在拉伸预应变大于应力平台时,两种变形方式在相同预应变后加热回复,SIM变形方式的逆相变温度和回复应变略高于MR变形方式.     

Influence of Carbon on the Microstructure of a Fe-Mn-Si-Cr-Ni Alloy

The influence of the addition of C to the Fe-Mn-Si-Cr-Ni base material is investigated at room temperature. Steel samples were deformed during a tensile experiment up to a strain of 17%. Light optical microscopy (OM) and x-ray diffraction (XRD) gave information about the different micro-structural phases that exist in the deformed and the undeformed alloys. The evolution of the defect structure is followed by positron annihilation techniques such as Doppler broadening of annihilation radiation spectroscopy (DBAR) and the positron annihilation lifetime spectroscopy (PALS). During deformation a martensitic ε-phase is induced. The size of the martensite plates increases with increasing deformation.     

Ti49.4Ni50.6超弹性弹簧的相变和形变特性

用示差扫描量热仪、拉伸实验和应力-应变循环实验系统研究了退火温度、变形温度以及热循环和室温应力-应变循环对Ti49．4Ni50．6超弹性(SE)弹簧的相变和形变特性的影响。冷加工加中温退火态Ti49．4Ni50．6合金冷却→←加热时的相变类型为母相B2→←R相→←马氏体B19′。随退火温度升高，马氏体转变温度升高，R相转变温度降低。623-773K退火态Ti49．4Ni50．6弹簧室温下可获得SE特性，随变形温度升高，SE弹簧剐度增加；当退火温度超过823K后，SE持性变差。热循环时SE弹簧的切变量取值越小，其应变恢复率越高。预循环训练可增强SE的稳定性。     

Effect of deformation on the stress-induced martensitic transformation in (Ni47Ti44)100−xNbx shape memory alloys with wide hysteresis

Martensite in TiNi-based alloys is reported to be thermally stabilized after a moderate deformation. Hence, this paper investigates the effect of deformation via stress-induced martensitic transformation on the reverse transformation behavior of (Ni₄₇Ti₄₄)_100−xNb_x (x=3, 9, 15, 20, 30 at.%) alloys. The stress-induced martensite appears to be stabilized in relation to the thermal-induced martensite that forms on cooling. This observation is confirmed by an increase in the reverse transformation start temperature, during which time the transformation temperature hysteresis reaches about 200°C. Moreover, the Nb content in Ni−Ti−Nb alloy has a great influence on the transformation temperature hysteresis of stress-induced martensite as well as on the process of stress-induced martensitic transformation. The mechanism of wide transformation temperature hysteresis is explained in terms of the microscopic structure of (Ni₄₇Ti₄₄)_100−xNb_x alloys. Furthermore, the temperature interval of the reverse transformation of stress-induced martensite was found to increase slightly as the strain of the high Nb-content alloy increased, though the value was much smaller than that of the thermally induced martensite. Finally, the paper explains the relation between this unique phenomenon and the elastic strain energy.     

马氏体相变

对前人所下的马氏体相变定义和所作的分类进行了总结,将马氏体相定义为：替换原子经无扩散切变位移（均匀的和不均匀的形变）由此产生形状改变和表面浮突,呈不变平面应变特征的一级,形核一长大型的相变,马氏体要变按动力学分为变温相变和等温相变,按热力学和界面动态分为弹性相变,近似（半）热弹性相变和非热弹性相变,热弹性相变的判据为（１）临界项相变动动力小,热滞小;（２）相界面能往复（正,逆）运动;（３）形状应变     

Phase volume fractions and strain measurements in an ultrafine-grained NiTi shape-memory alloy during tensile loading

An ultrafine-grained pseudoelastic NiTi shape-memory alloy wire with 50.9 at.% Ni was examined using synchrotron X-ray diffraction during in situ uniaxial tensile loading (up to 1 GPa) and unloading. Both macroscopic stress–strain measurements and volume-averaged lattice strains are reported and discussed. The loading behavior is described in terms of elasto-plastic deformation of austenite, emergence of R phase, stress-induced martensitic transformation, and elasto-plastic deformation, grain reorientation and detwinning of martensite. The unloading behavior is described in terms of stress relaxation and reverse plasticity of martensite, reverse transformation of martensite to austenite due to stress relaxation, and stress relaxation of austenite. Microscopically, lattice strains in various crystallographic directions in the austenitic B2, martensitic R, and martensitic B19′ phases are examined during loading and unloading. It is shown that the phase transformation occurs in a localized manner along the gage length at the plateau stress. Phase volume fractions and lattice strains in various crystallographic reflections in the austenite and martensite phases are examined over two transition regions between austenite and martensite, which have a width on the order of the wire diameter. Anisotropic effects observed in various crystallographic reflections of the austenitic phase are also discussed. The results contribute to a better understanding of the tensile loading behavior, both macroscopically and microscopically, of NiTi shape-memory alloys.