Nb,Ti微合金钢热变形的动态模拟变形抗力模型

本报道Ｎｂ，Ｔｉ微合金钢的热变形动态模拟变形抗力模型。在试验中用热加工模拟试验机进行高温压缩试验，其变形温度为１１２３－１４２３Ｋ，变形速率为０．１－６０ｓ＾－１。结果表明，在峰值以前该钢种的流变应力数学模型为：σ＝５．９９．ε＾０．１６７·ε＾（６．４７×１０＾－５·Ｔ）·ｅｘｐ（４０６４／Ｔ）。形变激活能（Ｑ）为４４４ｋｊ／ｍｏｌ，０β系数为０．０８０。峰值应力（σｐ），临界应变（εｃ）和…     

冷轧态SiCp/LY12复合材料超塑性及变形机制

研究了冷轧态ＳｉＣ颗粒（ｄｐ＝１０μｍ）增强ＬＹ１２复合材料（ＳｉＣｐ／ＬＹ１２）的超塑性,着重探讨了变形机制。研究表明：（１）在温度Ｔ＝８０３Ｋ（比熔点高２６Ｋ）,初始应变速度ε０＝４．８×１０＾－４ｓ＾－１时,应变速度敏感系数ｍ值为０．４９,延伸率达２４０％;（２）超塑性变形后的晶粒尺寸约为１０μｍ;（３）该事材料超塑性变形的主要机制是晶界液相和基体中动态回复调节的但却受界面液相和界面扩散流释     

快离子导体Na1＋xZr2—yV0.8ySixP3—xO12系统的制备与电性能研究

Ｎａｓｉｃｏｎ型快离子导体Ｎａ１＋ｘＺｒ２－ｙＭ０．８ｙＳｉｘＰ３－ｘＯ１２系统采用高温固相合成，春合成温度在１３７３Ｋ左右完成，该的合成温度在ｘ不变的情况下，随着ｙ的增大而降低，大多烽合成物为单斜晶系；空间群为Ｃ３／ｃ。当ｙ不变，ｘ增大地基地率的变化是先增大，后减小。最佳导一的起始组成为ｘ＝１．５、ｙ＝０．１，其电导率在室温时为３．２０×１０＾－４Ｓ／ｃｍ，在６７３Ｋ时为６．８８×１０＾－２Ｓ／     

Fe（OH）3中微量金属离子对水热合成α—Fe2O3粒径的影响

本文研究了某些金属离子（Ａｌ＾３＋、Ｍｎ＾２＋、Ｚｎ＾２＋、Ｃｒ＾２＋、Ｎｉ＾２＋、Ｃｏ＾２＋）Ｆｅ（ＯＨ）３凝胶经水热法合成的α－Ｆｅ２Ｏ３微粉颗粒大小的影响。研究结果出现，随着金属离子的浓度在一定范围内（０．０１０－０．０５０ｍｏｌ·Ｌ＾－１）的增加，α－Ｆｅ２Ｏ３颗粒有减小的趋势。其中加入Ｃｏ＾２＋（０．０５０ｍｏｌ·Ｌ＾－１）、Ｍｎ＾２＋（０．１００ｍｏｌ·Ｌ＾－１）可以得到粒径为７５ｎｍ     

新型L—乳酸盐酶电极的研制

本文研制一种新型乳酸盐酶生物传感器，此传感器以复合酶ＮＡＤ＾＋与ＬＤＨ共固定在经ＣＮＢｒ活化的琼脂糖上作为敏感膜。用厚为０．３ｍｍ的粒状琼脂糖制成的敏感膜电极，其响应性能最佳。此乳酸盐酶电极测试的最优条件是：在ｐＨ８．５的Ｔｒｉｓ－ＨＣｌ缓冲液中进行，温度２５℃，此缓冲液中含１．５ｍｍｏｌ·Ｌ＾－１ＶＫ３电子介体。此电极的线性反应范围为０．０４￣２．１μｍｏｌ·Ｌ＾－１，每μｍｏｌ·Ｌ＾－１乳酸盐     

双波长分光光度法测定工业废水中汞

在ｐＨ１２四硼酸钠缓冲溶液中，汞（Ｈｇ＾２＋）与新试剂，邻溴苯基重氮氨基偶氮苯（ＯＢＤＡ）反应生成红色鳌合物。本文研究μ修正双波长法测定汞及其鳌合物特性参数。研究结果表明：汞与ＯＢＤＡ组成比１：３，５００ｎｍ波长下，鳌合产物实际ε＝１．３１×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，其不稳定常数Ｋ＝１０＾－１４．２９。应用μ修正不等式理论证明了普通光度法对用该反应测定汞的准确性和可行性，废水测定表明：     

等离子体辅助反应式脉冲激光熔蚀制备AIN薄膜的低温生长

使用等离子体辅助反应式脉冲激光溅射沉积薄膜的方法在Ｓｉ（１１１）和Ｓｉ（１００）基片上已经成功地低温制备出ＡＩＮ多晶膜。实验表明,当脉冲能量密度ＤＥ＝１．０Ｊ·ｃｍ＾－２,脉冲频率ｆ＝５Ｈｚ,氮气气压ＰＮ２＝１．３３×１０＾４Ｐａ,基底温度ｔｓｕｂ＝２００℃,放电电压Ｖ＝６５０,基靶距离ｄｓ－Ｔ＝４ｃｍ时薄膜的生长速度等于６ｎｍ／ｍｉｎ。ＡＩＮ薄膜的折射率为２．０５,和基底的取向关系分别为：ＡＩＮ     

异步轧制取向硅钢薄带的三次再结晶

采用带比为１．２的异步轧制及常规轧制，将０．３０ｍｍ厚的工业取向硅钢冷轧至０．１０ｍｍ，在普通氢气炉中退火。对退火薄带的再结晶组织、织构和磁性的研究表明：经异步轧制并在１１５℃退火的５ｈ中发生了三次再结晶，晶粒度１￣３ｍｍ、晶粒取向为｛１１０｝［００１］；与冷轧前板材相比，薄带的磁性明显改善；铁损下降了５１％，Ｂ８＝１．９７８Ｔ，Ｐ１３／５０＝０．３０ｍＷ·ｇ＾－１，Ｐ１７／５０＝０．７２ｍＷ·ｇ     

A离子缺陷型钙钛矿La0.66TiO2.993的水热合成和表征

本文利用水热晶化法首次合成出正交钙钛矿结构的Ｌａ０．６６ＴｉＯ２２．９９３产物约３００ｎｍ粒径的多晶粉末，且有一定团聚现象，水热条件对合成的影响研究表明，最佳合成条件为：ＫＯＨ／Ｔｉ＝８０，Ｌａ／Ｔｉ＝０．７，（Ｔｉ）＝０．１ｍｏｌ．Ｌ＾－１，２６０℃下晶化７天。     

三溴偶氮胂直接光度法测定铝合金中铈组稀土元素

研究了铈组稀土元素与三溴偶氮胂（ＴＢＡ）的显色反应，在强盐酸介质中铈组稀土元素与ＴＢＡ形成蓝紫色络合物，其最大吸收在６３５ｎｍ，铈组稀土与ＴＢＡ的络合比为１：３，表观摩尔吸光系数为（１．１５￣１．２５）×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，在（０￣２５）μｇ／５０ｍＬ范围内遵守比耳定律。这个方法已应用于直接光度测定铝合金中的铈组稀土，并获得满意结果。     

Thermal conductivity of Cu–Zr/diamond composites produced by high temperature–high pressure method

Copper matrix composites reinforced with about 90 vol.% of diamond particles, with the addition of zirconium to copper matrix, were prepared by a high temperature–high pressure method. The Zr content was varied from 0 to 2.0 wt.% to investigate the effect on interfacial microstructure and thermal conductivity of the Cu–Zr/diamond composites. The highest thermal conductivity of 677 W m⁻¹ K⁻¹ was achieved for the composite with 1.0 wt.% Zr addition, which is 64% higher than that of the composite without Zr addition. This improvement is attributed to the formation of ZrC at the interface between copper and diamond. The variation of thermal conductivity of the composites was correlated to the evolution of interfacial microstructure with increasing Zr content.     

高压熔渗金刚石/铜复合材料的低温导热特性

为研究高压熔渗金刚石/铜复合材料导热率在低温区的变化规律,采用高压熔渗（HRF）的方法分别制备了不同粒度（100 μm,250 μm,400 μm）的金刚石/铜复合材料,利用扫描量热法分析评价了高压熔渗法制备的不同粒度金刚石/铜复合材料的低温导热特性,采用扫描电子显微镜（SEM）分析其显微组织。研究结果表明：由于高压熔渗制备的金刚石/铜复合材料中的部分金刚石发生聚晶反应,导致金刚石颗粒间晶界传热的热阻远小于界面传热热阻;高压熔渗条件下,金刚石颗粒内部变形破碎导致缺陷增多,且100~150 K低温下以声子为主要热载子的传热对裂纹和间隙等缺陷敏感,导致在较低温区内金刚石/铜复合材料的导热率低于普通压力熔渗（PF）所制备的金刚石/铜复合材料的导热率。     

金刚石膜/氧化铝陶瓷复合材料的介电特性和热学性能研究

研究了金刚石膜/氧化铝陶瓷复合材料作为超高速、大功率集成电路封装基板材料的可行性。采用电容法测量了复合材料的介电性质,结果表明在氧化铝上沉积金刚石膜,能有效降低基片材料的介电系数。碳离子预注入处理使介电损耗降低(从5×10^-3降低到2×10^-3),且频率稳定性更好。金刚石膜的沉积可明显提高基片的热导率,随着薄膜厚度的增加,复合材料的热导率单调递增。当薄膜厚度超过100μm时复合材料的介电系数下降到6.5、热导率上升至3.98W/cm·K,热导率接近氧化铝的20倍。     

Effect of coating on the microstructure and thermal conductivities of diamond-Cu composites prepared by powder metallurgy

Diamond-Cu composites from the direct combination of diamond and Cu show low thermal conductivities due to weak interface and high thermal resistance as a result of chemical incompatibility. In this paper, a new method is proposed to strengthen interfacial binding between diamond and Cu by coating strong carbide-forming elements, e.g., Ti or Cr on the surface of the diamond through vacuum micro-deposition. Interfacial thermal resistance of diamond-Cu composites is greatly decreased when diamond particles are coated by a Cr or Ti layer of a certain thickness before combining with Cu. Thermal conductivity is also increased several times. Cr coating can reduce more effectively interface thermal resistance between diamond and Cu than Ti coating. Moreover, it has a smaller negative impact on the thermal conductivity of the Cu matrix, resulting in higher thermal conductivity of Cr-coated diamond-Cu composites. Through the vacuum micro-deposition technology, Cr on the diamond particle surface is present in the form Cr₇C₃ near diamond and a pure Cr outer layer at 2:1. The optimum thickness is within 0.6-0.9 μm; at this depth, the thermal conductivities of 70 vol% diamond-Cu composites can be increased four times and reach as high as 657 W/m K. In this work, an original theoretical model is proposed to estimate the thermal conductivities of composite materials with an interlayer of a certain thickness. The predicted values from this model are in good agreement with the experimental values.     

Processing of diamond-particle-dispersed silver-matrix composites in solid–liquid co-existent state by SPS and their thermal conductivity

Diamond-particle-dispersed silver (Ag) matrix composite was fabricated in a unique fabrication method, where solid–liquid coexistent state of the powder mixture of diamond, pure Ag and pure Si was designed to create during spark plasma sintering (SPS) process. The composite is well consolidated in a temperature range between 1113 K and 1188 K and no reaction was detected by scanning electron microscopy at the interface between diamond particles and the Ag matrix. The relative packing density of the diamond–Ag composite fabricated was 95–97% in a volume fraction range of diamond between 40% and 50%. The thermal conductivity of the diamond–Ag composite containing 50 vol.% (v/o) diamond reached 717 W/mK, approximately 80% the theoretical thermal conductivity calculated by Maxwell–Eucken’s equation. This result suggests that the solid–liquid co-existent state during SPS consolidation is very effective not only for rapid densification of the composite but also for producing strong bonding between the diamond particles and the Ag matrix.     

放电等离子烧结制备Diamond/Al复合材料

采用放电等离子烧结法（SPS）制备了Diamond/Al复合材料,研究了金刚石粒径、成分配比、工艺参数等对复合材料的导热性能的影响。结果表明,SPS可以得到导热性能较好的Diamond/Al复合材料,致密度是影响该材料导热性能的最重要因素。在实验确定的金刚石体积分数50%,金刚石粒径70 μm,温度550℃、压力30 MPa的工艺条件下,所制备的材料致密度较高,热导率为182 W/(m·K),比相同条件下纯铝粉烧结体的热导率提高了34.8%,表明金刚石的添加对烧结铝基材料导热性能有明显的改善作用。      

Numerical investigation of the effect of interfacial thermal resistance upon the thermal conductivity of copper/diamond composites

Copper/diamond (Cu/D) composites are known for their applications in thermal management systems. This paper investigates the effect of interfacial thermal resistance (TR) upon the effective thermal conductivity of Cu/D composites through experimental and numerical means. The composite samples were made using uncoated, Cu-coated, and Cr-coated diamond particles. The transient plane source method was used to measure the thermal conductivity of the composite samples, while the micrographs of the specimens were used to develop the finite element models. Together with the experimental and numerical results, the interfacial TR was identified in each sample. Although Hasselman–Johnson model calculated the conductivity values with significant error, the trend shown by experimental results is still followed. The finite element model, however, led to an error of less than 1%. The numerical analysis showed that the TR depends not only upon the diamond volume fraction but also upon the coating material. Finally, it has been demonstrated that numerical simulation may be employed to reveal the appropriate combinations of diamond fraction and the coating material in order to attain the desired level of effective thermal conductivity.     

静电纺丝制备金刚石/聚丙烯腈杂化复合纤维

为了改善金刚石在聚合物中的均匀分散性,并提高导热性能,以不同粒度的金刚石和聚丙烯腈（PAN）共聚物为原料,采用静电纺丝方法制备得到金刚石/PAN杂化复合纤维。通过改变纺丝溶液中金刚石的添加量,研究了不同金刚石含量及不同粒度的金刚石对金刚石/PAN杂化复合纤维形态和热性能的影响。研究结果表明,静电纺丝可以有效解决微米级金刚石在PAN聚合物中的分散问题,金刚石的粒度对纺丝的稳定性和连续性影响很大,粒度为0.5~1 μm的金刚石经过纺丝可以有效地包覆在纤维中。当金刚石的粒度大于1~2 μm时,纺丝时稳定性差,纤维中很少或几乎没有包覆金刚石颗粒。当金刚石粒度为0.5~1 μm、实际质量分数为38.5wt%时,金刚石/PAN杂化复合纤维热导率最高,达到1.923 W/（m·K）。     

Thermal conductivity of CVD diamond films

Diamond films 60 and 170 µm in thickness were grown by PACVD (plasma-assisted chemical vapor deposition) under similar conditions. The thermal diffusivity of these freestanding films was measured between 100 and 300 K using AC calorimetry. Radiation heat loss from the surface was estimated by analyzing both the amplitude and the phase shift of a lock-in amplifier signal. Thermal conductivity was calculated using the specific heat data of natural diamond. At room temperature, the thermal conductivity of the 60 and 170 m films is 9 and 16 W-cm^–1. K^–1 respectively, which is 40–70% that of natural diamond, The temperature dependence of thermal conductivity of the CVD diamond films is similar to that of natural diamond, Phonon scattering processes are considered using the Debye model, The microsize of the grain boundary has a significant effect on the mean free path of phonons at low temperatures. The grain in CVD diamond film is grown as a columnar structure, Thus, the thicker film has the larger mean grain size and the higher thermal conductivity. Scanning electron microscopy (SEM) and Raman spectroscopy were used to study the microstructure of the CVD diamond films. In this experiment, we evaluated the quality of CVD diamond film of the whole sample by measuring the thermal conductivity.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Microstructural characterization and quantitative analysis of the interfacial carbides in Al(Si)/diamond composites

The existence of interfacial carbides is a well-known phenomenon in Al/diamond composites, although quantitative analyses are not described so far. The control of the formation of interfacial carbides while processing Al(Si)/diamond composites is of vital interest as a degradation of thermophysical properties appears upon excessive formation. Analytical quantification was performed by GC–MS measurements of gaseous species released upon dissolving the matrix and interfacial reaction products in aqueous NaOH solutions and the CH₄/N₂ ratio of the evolving reaction gases can be used for quantification. Although the formation of interfacial carbides is significantly suppressed by adding Si to Al, also a decline in composite thermal conductivity is observed in particular with increasing contact time between the liquid metal and the diamond particles during gas pressure infiltration. Furthermore, surface termination of diamond particles positively affects composite thermal conductivity as oxygenated diamond surfaces will result in an increase in composite thermal conductivity compared to hydrogenated ones. In order to understand the mechanisms responsible for all impacts on the thermal conductivity and thermal conductance behaviour, the metal/diamond interface was electrochemical etched and characterized by SEM. Selected specimens were also cut by an ultrashort pulsed laser system to characterize interfacial layers at the virgin cross section in the reactive system Al/diamond.