复合电沉积制备W-Ni-Cu梯度材料的组织及性能

采用熔盐电沉积与水溶液电沉积工艺制备了W-Ni-Cu复合材料。经800℃依次保温60、120、180 min退火后,可获得梯度层厚度分别为25、35、45μm的W-Ni-Cu梯度材料,其中Ni起到桥接W和Cu的作用。试样经热冲击和热疲劳试验处理后,表面无突起、裂纹或脱落现象,说明镀层与基体之间具有良好的冶金结合性能。导热性试验表明,在25~800℃范围内,纯W板和W-Ni-Cu梯度材料的导热系数随温度升高而降低;相同温度下,纯W板的导热系数比W-Ni-Cu梯度材料的导热系数大,且W-Ni-Cu梯度材料的导热系数随梯度层厚度升高而降低。     

超轻质ZrO2纤维隔热材料的热物理性能研究

采用Hot disk热分析仪和石英灯辐射加热法分别测试分析了ZrO<,2>纤维隔热材料的常温和高温隔热性能.研究表明,随材料孔隙率的增大,ZrO<,2>纤维隔热材料的有效导热系数减小,即隔热效果越好;在孔隙率相同的情况下,材料晶粒尺寸越小其有效导热系数就越小;随试样表面温度的升高,在热传导的过程中辐射起主导作用,从而使材料的有效导热系数增大;当温度由200℃升高到800℃时,ZrO<,2>纤维隔热材料的有效导热系数由0.027W/(m·K)升高到0.085W/(m·K),在800℃达到热稳定时,ZrO<,2>纤维隔热材料冷边的温度不高于30℃.     

基于一维稳态纵向导热法对几种铸铁材料热物理性能的研究

采用KY-DRX-JH金属高温导热系数测试仪,测定不同合金成分铸铁材料的导热系数。结果表明:在100～550℃,灰铸铁的导热系数随温度的升高呈下降趋势,蠕铁在100℃的导热系数低于灰铁,其导热系数范围为33.33～42.47 W/m·K;合金蠕铁的导热系数随温度的升高先升后降,峰值点在300℃左右。100℃时合金蠕铁的导热系数随基体中铁素体量的增加而提高。     

高速列车转向架用钢热物理性能

针对高速列车转向架材料Q345C和S355J2W(H)钢的导热系数、热膨胀系数、比热容、热扩散率热物理性能参数进行测试,建立高速列车转向架材料热物理性能基础数据库。结果表明,Q345C的Ac1为714℃,Ac3为850℃;S355J2W(H)的Ac1为732℃,Ac3为860℃。在常温~Ac1温度区间,随着温度的升高,热膨胀系数升高;在Ac1~Ac3温度区间,材料的热膨胀系数随温度的升高而降低;当温度高于Ac3时,材料的热膨胀系数又升高;温度低于Ac1时,比热容随温度升高而升高;当温度高于Ac1时,比热容随温度升高而降低,奥氏体转变完成后,比热容趋于定值。Q345C和S355J2W(H)两种材料的热扩散系数和导热系数随温度升高而降低。     

电沉积温度对熔融盐电沉积Ni/W复合层的影响

采用熔盐电沉积法制备了Ni/W复合层,通过扫描电镜,辉光放电光谱仪和电子背散射衍射技术对Ni/W复合层的微观结构、复合层厚度、晶粒尺寸及小角度晶界频率进行了表征。结果表明,Ni/W复合层的断裂方式为解理断裂;当电沉积温度为1073 K时,Ni/W复合层的表面平整光滑,晶粒尺寸大小均匀;随电沉积温度升高,复合层厚度逐渐增加,Ni在钨板中的扩散系数增大,小角度晶界频率增加。     

提高铝合金上电镀镍层结合强度的研究

采用一步电镀镍和特殊铝合金表面预处理方法，获得高结合强度的电镀镍层。选用热震法测试铝合金基体与沉积镍层之间的结合强度，讨论了铝合金电沉积镍层厚度、温度、电流密度对结合强度的影响。试验结果表明，在采用低电流密度0．2－0．5A/dm^2，镀层厚度8－15μm，电镀液温度15－25℃条件下，电镀镍层与铝合金的结合强度最高。     

梯度金属多孔材料孔结构研究

利用离心沉积技术在多孔管内壁上制备了不同粒度的镍和不锈钢多孔梯度层,研究不同粒度的粉末以及梯度层厚度对梯度层孔隙性能的影响.结果表明,梯度层透气系数与中流量孔在梯度层粒度为5 μm以下急剧减小,当梯度层粉末粒度为13.6μm、梯度层厚度小于20 μm时,梯度层厚度对其孔径分布与透气系数影响不大;当梯度层粉末粒度为2.7μm时,梯度层的最佳匹配厚度是50μm.     

2507双相不锈钢高温物理性能研究

采用综合热分析仪、热膨胀分析仪、激光导热仪和热/力模拟试验机分别对2507双相不锈钢进行了综合热分析试验、热膨胀试验、激光导热试验和高温力学试验,以控制连铸坯表面凹陷、裂纹等缺陷。结果表明：2507双相不锈钢的固相线温度为1 469.5℃,液相线温度为1 446.2℃;温度在100～750℃时,2507不锈钢平均线膨胀系数为16.606 1×10^-6 K^-1,温度在750～1 020℃之间的平均线膨胀系数为14.916 2×10^-6 K^-1,温度在1 020～1 400℃时平均线膨胀系数为20.475 1×10^-6 K^-1;在降温过程中,平均线膨胀系数为-22.690 3×10^-6 K^-1;2507不锈钢的密度随温度升高而降低;温度从650℃升至1 150℃,2507不锈钢的热扩散系数增大了25%;导热系数随温度升高而增大,在1 000℃时导热系数达到最大值34 W/(m·K);温度超过1 200℃之后,抗拉强度...     

W-Cu梯度功能材料的热物理性能

对采用不同粒度配比和热压制备的W-Cu梯度功能材料的热物理性能进行研究.结果表明:梯度材料的整体热导率较高,达到226.4 W/(m·K),高于过渡层W/Cu33的热导率,低丁散热层W/Cu50的热导率;封接层具有低的线性热膨胀系数,аRT-100℃=6,82×10-6/℃,满足与BeO基板材料封接匹配的要求;低温热压条件下制备的W-Cu梯度功能材料各梯度层的热膨胀系数具有良好的可控性和可设计性能,其实测值与理论值十分接近,其误差值低于6%;耐热冲击温度达到800℃以上,热疲劳性能可达500℃水淬50次以上.     

砂型铸造用型砂热物性参数的研究

利用数值模拟和试验的方法,研究了铸造生产用型砂的热物性参数。结果表明:型砂与铸件间距离对浇注后型砂温度变化影响明显;型砂导热系数随温度升高呈现"V"形变化趋势,即当型砂温度低于400℃时,型砂导热系数下降,温度高于400℃后,导热系数增加;而型砂的比热则呈现随温度升高而升高的趋势,但温度低于600℃时,比热明显增加,当温度高于600℃时,比热增加缓慢。     

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.