Fe—17Mn—10Cr—5Si—4Ni合金低温应力诱发相变特点及其形状记？…

用Ｘ射线衍射分析、显微组织观察等研究了Ｆｅ－１７Ｍｎ－１０Ｃｒ－５Ｓｉ－４Ｎｉ合金在低温（低于室温）下应力诱发相变的特点及其形状记忆效应。合金在室温拉伸变形时,当应变量超过５％由于应力诱发ε马氏体的相变作用而形成的α′马氏体;当变形温度低于室温时应力优先诱发γ－α′马氏体转变。正是这种应力诱发相应特征的转变使合金的形状记忆效应在室温以下出现奇特低谷。     

明效Fe—Mn—Si—Co—Mo合金中应力诱发马氏体的逆相变与形状记忆效应

研究了时效对Ｆｅ－Ｍｎ－Ｓｉ－Ｃｏ－Ｍｏ合金的临界屈服应力,应力诱发马氏体逆转变以及形状记忆效应的影响,结果表明,随着时效温度的升高,室温下的母相屈服应力与应力诱发马氏体相变临界应力之差增大,应力诱发马氏体逆转变温度Ａｃ和Ａｆ升高,而形状忘儿应在６００℃时效时出现峰值。     

X射线衍射法测定Fe-Mn-Si形状记忆合金层错几率的研究

Ｆｅ－Ｍｎ－Ｓｉ合金的形状记忆效应来源于马氏体相变,而马氏体相变则通过奥氏体内形成每隔一层｛１１１｝面上的堆垛层错来完成。与层错能相关的层错几率可能控制马氏体的相变机制。本文根据Ｗａｒｅｎ的衍射理论,用Ｘ射线衍射峰位移和峰宽化两种方法测定了Ｆｅ－Ｍｎ－Ｓｉ合金的层错几率,其结果表明随锰含量增加,层错几率降低。本文着重对提高衍射峰位移和峰宽化两种测定方法的精度及其影响因素进行详细的研究,并认为峰位移法更简便     

化学镀镍钴磷合金

对化学镀三元合金Ｎｉ－Ｃｏ－Ｐ镀层的材料性进行了研究，特别对Ｎｉ－Ｃｏ－Ｐ在元合金化学镀层的初期沉积行为及金相结构等进行了探讨，并讨论了磷含量对镀层的影响。     

预变形温度对Fe-Mn-Si-Ni-Cr合金形状记忆效应及Υ ε转变的影响

研究了不同预变形温度下Ｆｅ－２５Ｍｎ－４Ｓｉ－２Ｎｉ－Ｃｒ合金的形状记忆效应和Υ　ε转变。结果表明，在２０３Ｋ进行预变形可以获得最大形状恢复率；适当降低预变形温度有利于应力诱发发马氏体转变和形状记忆效应；但在７７Ｋ进行６％的预变形会使ε马氏体交割处产生全位错，不利于逆转变和形状记忆效应     

高温退火和时效处理对Ni47Ti44Nb9合金显微组织和马氏体相变的影响

本文用金相显微镜，电子探针和电阻率－温度曲线测试仪研究了高温退火和时效对Ｎｉ４７Ｔｉ４４Ｎｂｇ合金显微组织和马氏体相变的影响。结果表明，加热温度高于１０５０℃时，β－Ｎｂ相粒子聚集长大，但对马氏体相变并不产生明显影响。与富Ｎｉ的近等原子比Ｔｉ－Ｎｉ合金不同，Ｎｉ４７Ｔｉ４４Ｎｂｇ合金在时效过程中没有时效析出和时效硬化现象。Ｎｂ加入Ｔｉ－Ｎｉ合金中抑制了时效析出和Ｒ相变，从而降低了马氏体相变温度受热     

Fe－Mn－Si－Ni－Co合金中形变应力诱发ε马氏体的稳定化及其对记忆效应的影响

Ｆｅ－２５．６Ｍｎ－５．１Ｓｉ－４．１Ｎｉ－１．８Ｃｏ（ｗｔ％）合金在一８０℃变形时，可逆应变量ε＿ｒ随预应变量ε＿ｔ增大而迅速增大；当ε＿ｔ＞２．５％，增大速度减慢；当４．２％＜ε＿ｔ＜１０．８％，ε＿ｒ基本保持恒定值。逆相变温度Ａ＿ｆ随ε＿ｔ增大而连续升高，但Ａ＿ｓ不随ε＿ｔ变化。应力诱发ε马氏体及其逆相变后的残留显微组织分析表明，应力诱发ε马氏体片在形成过程中因相互交叉产生塑性变形，引起稳定化，是引起多晶Ｆｅ－Ｍｎ－Ｓｉ系合金可逆应变量低的一个重要原因。文中还讨论了应力诱发ε马氏体稳定化的特点及可能的改善途径。     

形状记忆材料的新进展

除高分子形状记忆材料外,按目前发展态势,将形状记忆材料分为四类(1)具热弹性马氏体相变、呈温控形状记忆效应(SME)的材料,(2)具半热弹性马氏体相变,由应力诱发马氏体,呈SME的材料,(3)具热弹性马氏体相变、由温控及磁控呈SME的铁磁材料,(4)具热弹性马氏体相变,在马氏体态由磁控呈现SME的材料.简述前一、二类材料的发展现状.阐述三、四类材料的研究现状和应用前景.     

一种新型功能晶体Ni2MnGa

Ｎｉ_２ＭｎＧａ晶体同时具有强铁磁性、大磁致伸缩、温控和磁控形状记忆效应,其磁控形状记忆效应的响应频率接近压电陶瓷,输出应变和应力接近温控形状记忆合金,是近年来发现的一类新型功能晶体．Ｎｉ_２ＭｐＧａ晶体７７Ｋ时在［００１］方向,仅２ＭＰａ的预应力即可产生５％的温控可回复应变,已接近 ＴｉＮｉ合金 ６％～８％的可回复应变量;非化学剂量的 Ｎｉ。ＭｎＧａ晶体室温条件下在［００１］方向, ６ ｈＯｅ外磁场已诱发产生 ０．３１％的输出应变,远超过巨磁致伸缩材料Ｔｅｒｆｅｎｏｌ－Ｄ输出应变０．１７％的水平．由于该晶体在磁场控制下表现出的大输出应变和应力,以及响应频率快和可精确控制的综合特性,使其可能在声纳、微位移器、线性马达、微波器件、振动和噪声控制、机器人和智能结构等诸多领域有重要应用,成为未来新一代驱动器和传感器材料．本文综述了Ｎｉ_２ＭｎＧａ单晶的基本性能、磁控形状记忆效应的机理、本质以及影响性能的因素等。     

预变形温度对Fe—Mn—Si—Ni—Cr合金形状记忆效应及γ←→ε转变的影响

研究了不同预变形温度下Ｆｅ－２５Ｍｎ－４Ｓｉ－２Ｎｉ－Ｃｒ合金的形状记忆效应和γ←→转变。结果表明，在２０３Ｋ进行预变形可以获得最大形状恢复率；适当降低预变形温度有利于应国诱发马氏体转变和形状忘儿应；但在７７Ｋ进行６％的预变形会使ε马氏体交割处产生全位错，不利于逆转变和形状记忆效应。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.