THE COMPOSITION AND THE CRYSTAL STRUCTURE OF CALCIUM SILICO-FLUORIDE PHASE A

In this paper,the composition formula of calcium silico-fluoride phase A is determined:19 CaO·TSiO_2·2CaF_2.The phase A is proved to be the primitive lattice of the orthorhombic system.The cellparameters a=12.29,b=7.09,c=56,9,α=β=γ=90°.D_(2h)~(13)--P_(nmm) or C_2~7--P_(nm)~2 are known to be the space group of phase A.     

THE GROWTH MECHANISM OF Al_2O_3/Al COMPOS-ITES BY DIRECTED OXIDATION OF MOLTEN METALS

The process of the directed oxidiation of al-loy Al-1%Mg-7%Si was invertigated by X-Ray diffraction(XRD),optical microscopy,scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),which in-cluded evolution of the surface of the melt in the incubationperiod,nucleation of Al_2O_3/metal composite and microstruc-ture of Lanxide material its growth front.Some new resultsabout the mechanism of the for mation of Al_2O_3 are involved.     

A HYPOTHESIS ABOUT THE MECHANISM OF ORIENTATION OF CH CRYSTAL IN INTERFACE LAYER BETWEEN CEMENT PASTE AND AGGREGATE

Some factors influencing the orientation index of CH crystal are mentioned, then a hypothesis about the mechanism of this orientation is proposed according to CH crystal structure and the principles of physical chemistry of surface, By thishypothesis it can be explained why the orientation of CH crystal is affected by some factors.     

THE SUPERCONDUCTIVITY OF SINGLE PHASE Ba_2YCu_3O_(9-x)SUPERCONDUCTING CERAMICS

The material of Ba_2YCu_3O_(9-x) superconductingceramics has been prepared.Its Ac susceptibility hasbeen measured by Ac mutual induction method.Itsresistance has been measured by the four-probe method.The results show that the first transition tempe-ture is 124K,the zero-resistance temperature is 98K.The results of X-ray diffractions indicate that thesuperconducting material is made up of the singlecrystal phase of Ba_2YCU_3O_(9-x) and that the crystalbelongs to the orthorhombic system with the crystal-line cell parameters of a=3.8182,b=3.8885,c=11.6874.     

THE PROCESS AND MECHANISM OF TiAl－BASED ALLOY SYNTHESIZED FROM Ti AND AlP OWDERS

ＴＨＥＰＲＯＣＥＳＳＡＮＤＭＥＣＨＡＮＩＳＭＯＦＴｉＡｌ－ＢＡＳＥＤＡＬＬＯＹＳＹＮＴＨＥＳＩＺＥＤＦＲＯＭＴｉＡＮＤＡｌＰＯＷＤＥＲＳＸｉｏｎＡｘＸｉａｎｙ；ＨｕａｎｇＢａｉｙｕｎ（ＰｏｗｄｅｒＭｅｔａｌｌｕｒｇｙＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｉｅ...     

CURE OF PREPOLYMER BASED ON METHYL METHACRYLATE/STYRENE AND OPTICAL PROPERTY AND HYDROTHRMAL STABILITY OF TRANSPARENT FIBRE—REINFORCED THERMOPLASTIC COPOLYMER COMPOSITES

Copolymers used for transparent.fibre glass-reinforcedthermoplastic composite were prepared from methyl methacrylate(MMA)and styrene (St).Composites containing 20～25 wt% glassfibre and 0.7 mm in thickness had an overall optical transmission of 88～90%.The gel time and cure time of the prepolyners from MMAand St decreased markdly with addition of the two linear unsaturatedpolyesters(LUPE)and curing process of composite laminate becamecontrolling easily,The effect of the concentration of LUPE on thermalstability of copolymers.the optical properties and the hydrothermal sta-bility of composites was investigated by comparing with those of trans-parent unsaturated composites.     

CREEP－RUPTURE BEHAVIOR OF Al－Li－Cu－Mg－Zr ALLOY IN THE TEMPERATURE RANGE OF 463～563K~＋

ＣＲＥＥＰ－ＲＵＰＴＵＲＥＢＥＨＡＶＩＯＲＯＦＡｌ－Ｌｉ－Ｃｕ－Ｍｇ－ＺｒＡＬＬＯＹＩＮＴＨＥＴＥＭＰＥＲＡＴＵＲＥＲＡＮＧＥＯＦ４６３～５６３Ｋ~＋￥ＺｈｅｎｇＺｉｑｉａｏ；ＬｉａｎｇＳｈｕｑｕａｎ；ＬｉｕＭｉｎｇｇｕｉ；ＹｉｎＤｅｎｇｆｅｎｇ（Ｄ?..     

TiNi形状记忆合金的阻尼特性及应用

从工程中一种常见的机器隔振模型出发 ,运用导纳模态方法 ,得出了输入到基础梁的功率流表达式 .根据试验数据模拟了形状记忆合金的超弹性循环曲线并计算了TiNi形状记忆合金丝在一定振幅下循环加卸载时的超弹性等效阻尼 ,并将记忆合金丝作为一种等效阻尼材料应用到隔振模型中 .通过计算机仿真 ,得出在此模型中使用记忆合金丝作为阻尼材料及用与合金丝在几个频率时的等效阻尼相当的普通阻尼材料时输入到基础的功率谱图 ,分析了记忆合金作为阻尼材料时对模型隔振效果的影响 ,从而得出其作为阻尼材料的优越之处     

Fe—Mn—Si基形状记忆合金及其应用

介绍了形状记忆合金的简要发展史,Fe-Mn-Si合金的形状记忆机理以及合金的主要元素组成,各成分的作用,提高记忆的方法,分析了其应用情况和前景。     

Effect of chemical component on shape memory effect of Fe-Mn-Si-Ni-C-RE shape memory alloy

Effect of chemical component on shape memory effect (SME) of Fe-Mn-Si-Ni-C-RE shape memory alloys was studied by bent measurement, thermal cycle training, SEM etc. Results of study indicate that the alloys with high Mn content (25%) appeare better SME, especially in lower strain. SME improves evidently when Si is higher content, especially it‘s range firm 3% up to 4%.But brittleness of Fe-Mn-Si-Ni-C-RE alloy increases by increasing the Si content. SME of the alloy is weakening gradually as carbon content increases under small strain (3%). But in the condition of large strain (above 6%), SME of the alloy whose carbon content ranges from 0.1% to 0.12% shows small decreasing range, especially of alloy with the addition of compound RE.     

A free-cutting and ductile CuAlMnZnTiB shape memory alloy

The mechanical properties and cutting performance of the designed Cu Al Mn Zn Ti B shape memory alloy were studied by tensile test and microstructure observation. Using X-ray diffractometry, differential scanning calorimetry(DSC) and semi-quantitative shape memory effect test, the microstructure and shape memory effect were analyzed. It is found that lots of βphase and few α phase are formed in the quenching of Cu-7.5Al-9.7Mn-3.4Zn-0.3Ti-0.14B(mass fraction, %) alloy, a great deal of martensite and few α phase are formed in the aging alloy, while the annealing alloy is composed of a great deal of α phase and few βphase. The tensile strength and elongation of the annealed alloy are 649 MPa and 17.1%, respectively. Some tiny and dispersion distributed second phase particles are generated in Ti and B precipitates, greatly improving the alloy machinability.     

形状记忆合金驱动器的力学性能

基于形状记忆合金（ＳＭＡ）材料的Ｂｒｉｎｓｏｎ本构关系,研究了ＳＭＡ驱动器在自由冷却和强制冷却等两种热交换形式下的动力响应问题,探讨了ＳＭＡ丝在恒载及荷载变化时完成正逆相变所需用的时间．研究结果表明,热交换方式对完成相变时间有较大影响,并且增加散热面积和提高热交换速率均可有效地加速相变的完成．最后,本文还简单讨论了影响ＳＭＡ驱动器响应时间的几个因素和改进方法．     

Ni－Ti合金中基体柱状晶的取向分布规律

柱状晶的生长都具有一定的取向,形状记忆效应与柱状晶的生长取向有着非常直接的关系。我们利用Ｘ射线衍射仪可测出Ｎｉ－Ｔｉ合金柱状晶生长取向「１００」Ｂ２随着衍射角θ＾′的变化规律,从而对利用和推广形状记忆合金有着极为现实的意义。     

NiTi形状记忆合金应变传感特性分析

阐述了形状记忆合金丝的应变传感原理.在Brinson建立的形状记忆合金一维本构模型的基础上,引入Ikuta提出的电阻率与马氏体百分含量之间的关系并对其进行简化,建立了形状记忆合金应变传感特性的理论分析模型.分析了不同温度条件、不同初始状态的形状记忆合金电阻相对变化率与应变之间的关系.并与已有试验结果进行比较,验证了该模型的有效性.结果表明,形状记忆合金可以作为应变传感元件使用,温度对形状记忆合金的传感特性有影响,设计时要根据使用温度来确定形状记忆合金的相变温度.     

Constitutive model for shape memory alloy torsion actuator

Shape memory alloy ( SMA) torsion actuator is one of the key approaches realizing adaptive wings in airplanes. In this paper,the actuator is made up of SMA wires and a thin-walled tube,in which the SMA wires are twisted and affixed around the surface of the tube at an angle referenced to the center axis of the tube. A thermo-mechanical constitutive model is developed to predict the thermo-mechanical behaviors of the SMA torsion actuator based on the knowledge of solid mechanics. The relationship between the torsion-angle and tem- perature is numerically calculated by using the thermo-mechanical constitutive model coupled with the SMA phase transformation model developed by Zhou and Yoon. The numerical results are compared with the relative experimental results finished by Xiong and Shen. Influences of the twist-angle of SMA wires and geometrical factors on the primary actuation performances of the SMA torsion actuator are also numerically investigated based on the thermo-mechanical constitutive model coupled with the SMA phase transformation model developed by Zhou and Yoon. Results show that the thermo-mechanical constitutive model can well predict the thermo-mechanical behaviors of the SMA torsion actuator.     

Low Velocity Impact Response Analysis of Shape Memory Alloy Reinforced Composite Beam

The low velocity impact responses of shape memory alloy （ SMA ） reinforced composite beams were analyzed by employing the finite element method. The finite element dynamic equntion was solved by the Newmark direct integration method, the impact contact force was determined asing the Hertzian contact law, and the influence of SMA .fibers on stiffiwss matrix is studied. Numerical results show that the SMA fibers can effectively improve the low velocity impact response property of composite beam.     

形状记忆合金迟滞模型

基于实验测试,结合Preisach理论研究了形状记忆合金(Shape memory alloy,SMA)丝驱动器的迟滞建模。首先,依赖于SMA材料受输入电压作用引起的温升变化诱发材料相变输出位移量,设计了SMA丝特性测试平台,记录了驱动过程中的输入、输出变化量,得到理论模型参数辨识的数据集合。然后,讨论了SMA丝的输入电压、温度变化与形状记忆效应产生的材料宏观位移间的迟滞关系。最后,引入Preisach理论,由推导的经典Preisach理论的修正形式和数值实现方法构造了SMA驱动器温度量和位移的迟滞模型。结果表明:与试验数据比较,Matlab环境仿真得到的SMA迟滞曲线,匹配性较好,为进一步的系统设计分析奠定了基础。