Co-Ni合金的马氏体转变特性和形状记忆效应

研究了Co-Ni合金的形状记忆效应(SEM)和马氏体转变动力学。发现形状记忆效应随着Ni含量的增加而下降，并且与原有ε马氏体含量成正比。这表明Co-Ni合金的形状记忆效应与原有ε马氏体片的聚集有关。α→←ε之间的热循环处理增加了ε马氏体的含量，并且随着循环次数的增加，形状记忆效应增大。Co-Ni合金的马氏体相变动力学可以表达为：Y=1-exp[-0．00526(Ms-25)]其中Y为ε马氏体的体积分数，Ms为马氏体转变起始温度(℃)。     

Co-Ni合金的马氏体转变特性和形状记忆效应

研究了Co_Ni合金的形状记忆效应 (SEM)和马氏体转变动力学。发现形状记忆效应随着Ni含量的增加而下降 ,并且与原有ε马氏体含量成正比。这表明Co_Ni合金的形状记忆效应与原有ε马氏体片的聚集有关。α ε之间的热循环处理增加了ε马氏体的含量 ,并且随着循环次数的增加 ,形状记忆效应增大。Co_Ni合金的马氏体相变动力学可以表达为 :Y =1 -exp[- 0 .0 0 5 2 6 (Ms- 2 5 ) ],其中Y为ε马氏体的体积分数 ,Ms 为马氏体转变起始温度 (℃ )。     

Cu-11.1Al-6.5Mn-1.6Zn-0.1Zr形状记忆合金的母相时效效应及其机理研究

研究了母相时效对Cu-11．1Al-6．5Mn-1．6Zn-0．1Zr合金形状记忆效应的影响，应用X射线衍射、扫描电镜等分析了时效过程中该合金相变、组织形态、晶体结构等变化。结果表明：在300℃以下温度时效，Cu-11．1Al-6．5Mn-1．6Zn-0．1Zr合金具有较强的形状记忆稳定性，当时效温度超过350℃时，因发生共析转变(β→α γ2)，使其形状记忆效应显著降低。     

热处理对激冷Ti-50Ni合金薄带相变和形状记忆行为的影响

用甩带法制备了Ti-50Ni形状记忆合金薄带,用X射线衍射仪、扫描电镜、透射电镜、示差扫描量热仪和弯曲试验研究了Ti-50Ni合金薄带的相组成、显微组织、相变行为和形状记忆效应。结果表明,铸态和400~600℃退火态Ti-50Ni合金薄带的显微组织形态呈树枝状,由马氏体相B19'和母相B2组成,加热/冷却过程中发生A→R→M/M→R→A(A-母相,R-R相,M-马氏体)二阶可逆相变。随退火温度升高,Ti-50Ni合金薄带的相组成和显微组织形态变化不大;马氏体逆相变温度T_A、R正相变温度T_R、R逆相变温度T_(Rr)和马氏体相变热滞ΔT_M升高,马氏体正相变温度T_M下降,R相变热滞ΔT_R缓慢降低;M逆相变峰向高温移动,逐渐与R逆相变峰合并。铸态和退火态Ti-50Ni合金薄带皆具有良好的形状记忆效应。     

Ni—Ti形状记忆合金增强的铝基复合材料

采用粉末冶金方法可将Ni-Ti形状记忆合金(SMA)添加到铝基体中，利用Ni-Ti SMA的形状记忆效应强化基体材料，提高基体材料的抗疲劳性能。1 颗粒强化机理将Ni-Ti SMA粉末弥散于铝基体中，制成复合材料，急冷到马氏体相变温度以下(大约低20℃)，在Ni-Ti颗粒中就会生成马氏体相，再将复合材料进行10%的冷轧变形。由于Ni-Ti中的马氏体相和铝基体相比，具有较低的屈服强度和模量，因此，在冷轧过程中Ni-Ti颗粒也会变形。当把复合材料再加热到奥氏体相变温度以上时，Ni-Ti颗粒发生相变，出现形状记忆效应，并且回复到形变前的原始形状。…     

单程和双程TiNi形状记忆合金的相变行为

用差示扫描量热仪(DSC)和透射电子显微镜(TEM)研究了具有单程和双程形状记忆效应的近等原子比 TiNi 合金的相变行为。结果表明,在降温过程中,单程和双程记忆合金的相变行为分别为B_2→M 和B_2→R→R+M。R 相变属于一级相变,它不是予马氏体,而是和双程记忆效应相关的。     

马氏体相变研究的进展(二)

概述对马氏体相变基本特征认识的进程，以及与马氏体相变密切相关的形状记忆材料的发展。对马氏体相变热力学、动力学、晶体学、形核-长大、非线性物理模型以及形状记忆效应、伪弹性和伪滞弹性研究进展作了总结。对马氏体相变的继续研究和应用作了展望。     

Cu—Zn—Al形状记忆合金在马氏体状态的塑性变形

采用光学显微镜、电子显微镜、电阻和膨胀方法研究了三种Cu-Zn-Al形状记忆合金在马氏体状态的塑性变形对马氏体转变温度、相变过程及转变循环滞后的影响。其中两种合金相变温度较高,在室温下即为马氏体状态。第三种合金A_f温度远低于室温。讨论了“第一次循环效应”的可能机制。     

形变退火态Ti-50.8Ni-0.1Nb合金的相变和形状记忆行为

用XRD、光学显微镜、示差扫描量热仪和拉伸实验研究退火温度(t_a)对冷拉Ti-50.8Ni-0.1Nb(摩尔分数,%)合金组织、相变和形状记忆行为的影响。结果表明:350～700℃退火态Ti-50.8Ni-0.1Nb合金由马氏体M(B19′,单斜结构)和母相A(B2,Cs Cl型结构)组成。随t_a升高,合金组织形貌由纤维状变为等轴状,再结晶温度约为580℃;合金冷却/加热相变类型由A→R→M/M→R→A型向A→R→M/M→A型向A→M/M→A型转变(R-R相,菱方结构),R相变温度降低,M相变温度和热滞先升高后降低,R相变热滞为6.7～9.8℃。350～550℃退火态合金的抗拉强度高于600～700℃退火态合金的,伸长率则远低于后者的。400～550℃退火态合金呈形状记忆效应,350℃退火态和600℃及以上温度退火态合金呈超弹性。随应力-应变循环次数增加,合金应力-应变曲线的平台应力下降。400～550℃退火态合金的形状记忆效应和600℃及以上温度退火态合金的超弹性稳定性良好。     

形状记忆不锈钢

新近开发成功的ＦｅＭｎＳｉＣｒＮｉ形状记忆不锈钢具有良好的形状记忆效应 ,同时还具有很好的力学性能、机加工性、焊接性和耐蚀性 ,而且是这类功能材料之中最廉价的合金。形状记忆不锈钢具有低的堆垛层错能 ,其形状记忆效应涉及到应力诱发的面心立方奥氏体 (γ)向密排六方ε 马氏体的相转变及其在加热时的逆转变。其形状记忆效应的先决条件就在于能直接引起ε 马氏体形成的宽的堆垛层错。因此 ,可以通过以下措施来改善这种形状记忆不锈钢的形状记忆效应 ;降低堆垛层错能 ;提高奥氏体基体的屈服应力 ;减低马氏体相变的临界应力 ;避免不同…     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.