NiTi合金中应力诱发马氏体相变过程的强度和电阻特性

研究了ＮｉＴｉ合金中应力诱发马氏体相变过程相过程的强度特性和电阻特性，并讨论了上术特性的物理本质。研究表明：变形过程的强度和电阻同步测能确切有效地阐明材料的畸变，再取向和相变特性。     

Cu-Zn-Al合金中马氏体相变的动态观察

Cu70Zn26Al4合金中存在马氏体转变,高压电镜(1000kV)和分析电镜的观察表明,在室温下的平衡母相为β’相(DO_3型),有部份淬火马氏体、表面马氏体存在,还有少量的γ相。在相变过程内,样品中有微裂纹产生和扩展;在冷却实验中,马氏体以母相的(101)面为基面,新相结构为M12R+2H型,没有择优取向问题。在应力诱发马氏体相变中,马氏体以母相的(110)面为基面,新相结构为M18R,存在择优取向问题。在冷却实验中和应力诱发马氏体相变中,都存在β相的预转变,预马氏体的9R和12H衍射极大。在应力诱发马氏体相变中,预马氏体的出现与否与应力施加的速率有关。     

有色合金的热弹性马氏体相变及其应用

综述本文作者及其合作者对有色合金的热弹性马氏体相变及其在形状记忆中应用的已发表的工作。在热力学研究、M_s 及 A_s 计算的基础上,本文提出材料中发生热弹性马氏体相变的必需条件。扼要总结我们对 Ni-Ti 及 Cu-Zn-Al 合金中的相变及形状记忆效应的工作。     

Ni-Ga-Fe-Co铁磁形状记忆合金的磁性转变和马氏体相变

Ferromagnetic shape memory alloys (FSMAs) such as NiMnGa, FePd and FePt are attractive as a new magnetic actuator material. They show a large magnetic-field-induced strain of 3% - 9% due to the variant rearrangement. Recently, the present authors have reported that in the Ni-Ga-Fe alloy the martensitic transformationfrom the B2 and/or the L21 structures into a seven-layer or five-layer modulated structure occurs upon cooling. In this alloy system, however, it is impossible to obtain a martensite phase at RT with a Curie temperature (To) higher than 100℃. In this work, the effects of substitution of Co for Ni on the martensitic and magnetic transformations, crystal structures and phase equilibria in Ni-Ca-Fe alloys were studied. Ni-Ga-Fe-Co alloys were prepared by induction melting under an argon atmosphere. Small pieces of specimens were taken from the ingot and homogenized at 1433 K for 24 h followed by quenching in water. The obtained specimens were aged at 773 K for 24 h and then quenched. The compositions of each phase were determined by energy dispersion X-ray spectroscopy (El)X). The martensitic transformation temperatures and Tc were measured by differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM) measurement. The crystal structure of martensite phase was observed by X-ray diffractmeter (XRD) and transmission electron microscope (TEM). The Curie temperature Tc was increased with increasing Co content while the martensitic transformation temperature slightly decreased. In the Ni(54-x) Ga27 Fe19 Cox, Tc increases from 303 K to 408 K with increasing CO content from x=0 to x=6. The crystal structure of the martensite phase and the phase equiribria in the Ni-Fe-Ga-Co alloys will be also presented.     

钛合金的马氏体相变

本文简要阐述了钛合金马氏体相变的原理、特点和应用, 并对钛合金热处理工艺作了叙述。     

合金元素对马氏体时效不锈钢Ms温度影响的定量分析

在现有各钢种马氏体转变开始温度 (Ms)经验计算公式的基础上 ,分析了合金元素对钢的Ms的影响 ,经验算提出马氏体时效不锈钢的Ms(℃ ) =5 5 0 - 330C - 35Mn - 1 7Ni - 1 2Cr - 2 1Mo - 1 0Cu - 5W - 1 0Si-0Ti+1 0Co +30Al。用该经验公式得出马氏体时效不锈钢Ms计算值与试验值符合较好 ,误差范围± 2 0℃ ,平均误差 1 1 .2 2℃。     

铁合金马氏体逆相变的织构研究

研究了在不同组织状态冷轧的Ｆｅ－３０Ｎｉ合金从马氏体到奥氏体逆相变过程中的织构变化。原始材料的组织状态为形变马氏体、淬火马氏体及残余奥氏体。经过在不同温度加热后，利用Ｘ射线衍射精确测量了马氏体及奥氏体的完全极图。结果表明，在不同组织状态下冷轧的Ｆｅ－３０Ｎｉ合金，经过γ－α－γｒ相变循环后，原冷轧奥氏体织构均得以恢复，逆相变奥氏体的取向分布只与原冷轧奥氏体的取向分布有关，与马氏体取向分布无关。     

Cu-Zn合金马氏体相变中的内耗、电阻与形变

通过对Cu-Zn合金的内耗、电阻、形变、频率和温度的同步测量,发现了这些量的变化过程存在一定的联系。另外对Cu-Zn合金热弹性马氏体相变的电阻峰进行了定量研究,所得公式与实验结果很好地符合。     

Ce—TZP的马氏体相变

加入稳定剂的 ZrO_2陶瓷具有高强度、高韧性,是三大结构陶瓷之一。从立方基体中析出的四方 ZrO_2孪晶转变为单斜 ZrO_2(发生马氏体相变),即形成部分稳定氧化锆(PSZ)。由于 PSZ 中可发生马氏体相变的四方相晶粒少,增韧效果不理想,近十几年人们又研究出氧化锆增韧陶瓷(TZP),主要包括 Y-TZP 和Ce-TZP。Ce-TZP 的韧性和强度较理想,并且发现具有形状记忆效应。1987年美国密执根大学在含量为12     

Y—PSZ的马氏体相变

(一)试验方法 由上海工业大学提供纯ZrO_2和Y-PSZ(氧化钇稳定的部分稳定氧化锆)粉末,平均粒径为0.05～0.1μm。在医用压片机上将混有成型剂的粉末压制成19×14×2mm的薄片,经脱除成型剂后,在箱式硅化钼炉中于1450～1500℃保温2h烧结成约13.5×10 ×1.5mm的瓷片作为X射线衍射试样。常温X射线衍射在菲利浦APD-10全自动X射线衍射仪上进行。高、低温X射线衍射在日本理学     

Fe—Ni—Mn合金中的逆马氏体转变

据“《Metallography》1987,No.4报道鉴于已有文献提供的Fe—Ni—Mn合金中马氏体转变的显微组织结构细节,因此本工作研究了在一种这类合金中通过逆马氏体转变而产生的二次奥氏体的形核和长大。 1 实验取成份为Fe—19.8 Ni—5.25 Mn—0.009C(wt.％)的合金,从大块料上切取4×10×15mm的试样。于室温下,将其一部份轧到约150μm厚,便于以后电镜研     

NiAl合金的B2→L10（3R）马氏体相变晶体学研究

根据ＮｉＡｌ合金的三种Ｂ２→Ｌ１０（３Ｒ）马氏体相变表象理论模型，从原子迁动的晶体几何关系出发，讨论了Ｂ２→Ｌ１０（３Ｒ）马氏体相变晶体学及２４种马氏体变体间的位向关系。对分别由这三种相变机制形成的２４种马氏体变体之间的晶体学等价关系进行了详尽的说明     

FeMnSi系形状记忆合金的εM马氏体相变研究

用透射电镜和高分辨率电镜研究了Ｆｅ１７Ｍｎ５Ｓｉ１０Ｃｒ５Ｎｉ合白的应力诱发εＭ形态。生长初期εＭ为厚约２０ｎｍ的薄片,它在长度方向上是不连续的,间断区为各生长单元的前沿区。生长初期的εＭ薄片在交叉时可利用本身的间断区而相互贯穿,且不留下交互作用痕迹,由εＭ薄合合并成宽大的ε。这种结构特点决定了宽大的δＭ薄片交互作用的复杂性。     

Fe-Ni-Si基奥氏体时效合金的马氏体相变和形状记忆效应

It is well known that the morphologies of the α martensite formed from the γ phase in ferrous alloys are classified into five types of lath, butterfly, (225)A type plate,lenticular and thin-plate. Among those α martensites, onlythe thinplate martensite, which is characterized by containing a high density of transformation twins, has a potential of exhibiting a perfect shape memory (SM) effect.Recently the present authors found in Fe-Ni-Si alloys that the thin-plate martensite is formed by the introduction of fine and coherent γ-(Ni,Fe)3Si particles with a L12 ordered structure in the austenite matrix due to ausaging. In the present study, the SM properties of the ausaged Fe-Ni-Si alloys with the thin-plate martensite are investigated by a conventional bending-test. The effects of the addition of Co to the Fe-Ni-Si alloys on the martensitic transformation and the SM properties are also investigated. It is shown that while the ausaged Fe-Ni-Si ternary alloys exhibit an imperfect SM effect due to reverse transformation from stress-induced thin-plate martensite to austenite, the SM properties are improved by the addition of Co. An almost perfect SM effect is confirmed in the Fe-Ni-Si-Co alloys by heating to 1 100 ℃ after deformation at -196 ℃.     

稀土对低碳钢马氏体相变的影响

０．２７Ｃ－１Ｃｒ钢中加入稀土，细化奥氏体晶粒，降低Ｍｓ，缩小马氏体条宽，减少残余奥氏体量，并抑制自回火过程。稀土偏聚在原奥氏体晶界，不因马氏体盯变而改变。根据以往证明：低碳钢马氏体相变中存在碳的扩散，则低碳钢淬火后的残余奥氏体量不但决定于Ｍｓ和淬火介质温度（Ｔｑ），还受合金元素对碳扩散的影响。由此将Ｍａｇｅｅ公式修改为：γ（％）＝ｅｘｐ［α（Ｃ１－Ｃ０）－β（Ｍｓ－Ｔｑ）］其中Ｃ０和Ｃ１分别为淬     

Cu—Zn—Al系合金热弹性马氏体相变的热滞

本文通过热处理工艺及添加第四组元研究了Cu－Zn－Al系记忆合金的相变热滞。结果表明，淬火冷却速度影响合金的相变热滞大小，随着母相时效时间的延长，马氏体相变热滞变大．Mn元素的加入可以减小CU－Zn－Al合金相变热滞．