热处理工艺对6063铝合金强度和导电率的影响

研究了热处理工艺参数(如时效温度、时间等)对6063铝合金的强度和导电率的影响。结果表明，低温长时间和高温短时间都可以提高强度，而随着时效温度的提高和时效时间的延长，6063铝合金的导电率呈上升趋势。     

高强度高导电的形变Cu-Fe原位复合材料

通过合金成分和变形工艺研究, 制备了一种高强度高导电性的形变Cu-Fe原位复合材料.实验结果表明, 铁含量越高, 强度越高, 导电性越低; 加入少量镁或锆, 可提高强度, 但同时损失导电性.在变形过程中, 加入适当的中间热处理, 在改变强度不太大的前提下, 能大大提高导电性.通过合理选择合金成分和变形工艺流程, 可制备不同强度和导电性等级要求的Cu-Fe原位复合材料.     

热处理工艺对Cu-Fe-P合金显微硬度及导电率的影响

自行设计了一种Cu Fe P系合金 ,研究了固溶温度、时效温度以及时效时间对该合金显微硬度和导电率的变化规律。结果表明 ,该合金的最佳固溶处理工艺为 90 0℃× 70min ,并在 4 0 0℃× 2h时效条件下具有较好的综合性能 ,显微硬度可达到 10 6 4HV0 1,导电率可达 82 3%IACS。试验结果还表明 ,在 4 0 0℃、5 0 0℃下时效 ,随着时间的延长合金显微硬度会出现两个峰值。     

MICROSTRUCTURE AND PROPERTIES OF C-Cu NANOSTRUCTURE THIN FILM

Nanostructured C-Cu thin films were deposited by reactive sputtering method and co-sputtering method. The relationships between microstructures, properties, and depo-sition parameters were studied and the results obtained from TEM, AFM, and XPS.indicate that the thin films are nanostructural, and have good in-depth uniformity. Theselected area electron diffraction (SAED) found that the nanosize Cu particles havethe fcc structure and the others are amorphous carbon or nanocrystallized graphiticcarbon. The peak positions of the Cu and C in XPS indicate them to be at the ele-mental state. In the IR transmission spectrum, diamond two-phonon absorption andgraphite Raman peaks were observed, which suggests microcrystal diamond particlesand graphite components exist in the C-Cu film. The higher electrical resistivity wasobtained.     

Performances of electrically heated microgroove vaporizers

An electrically heated microgroove vaporizer was proposed. The vaporizer mainly comprised an outer tube, an inner tube and an electrical heater cartridge. Microgrooves were fabricated on the external surface of the inner tube by micro-cutting method, which formed the flow passage for fluid between the external surface of the inner tube and the internal surface of the outer tube. Experiments related to the temperature rise response of water and the thermal conversion efficiency of vaporizer were done to estimate the influences of microgroove＇s direction, feed flow rate and input voltage on the performances of the vaporizer. The results indicate that the microgroove＇s direction dominates the vaporizer performance at a lower input voltage. The longitudinal microgroove vaporizer exhibits the best performances for the temperature rise response of water and thermal conversion efficiency of vaporizer. For a moderate input voltage, the microgroove＇s direction and the feed flow rate of water together govern the vaporizer performances. The input voltage becomes the key influencing factor when the vaporizer works at a high input voltage, resulting in the similar performances of longitudinal, oblique and latitudinal microgroove vaporizers.     

Experimental study of NiO electrical conductivity changes under low oxygen pressures

The electrical conductivity of NiO was measured at 740°C in an oxygen pressure range of 10^–2 –1.3 Torr. By means of continuous recording, longtime experiments were performed. The results show that for any admittance of oxygen, the electrical conductivity initially increased and then decreased to its initial value. For pressures higher than 0.1 Torr the decrease of the signal was reduced and the time required to attain the initial value sometimes reached several days. These results suggest that the electrical conductivity changes may be considered as a transitory phenomenon connected to attaining gassolid equilibrium.     

La0．8Ca0．2CrO3钙钛矿复合氧化物的GNP法合成与表征

采用GNP（Glycine-Nitrate Process）法合成La0.8Ca0.2CrO3初级粉料，研究甘氨酸用量对产物的晶体结构和显微形貌的影响，并测试烧结体的相对密度和电导率。研究结果表明，甘氨酸与金属离子的摩尔比（G／M^n＋）控制在2．0～2．5时可得到颗粒尺寸细小、均匀（100nm～200nm）的单相钙钛矿粉体，烧结温度为1350℃时样品的相对密度达到91．0％，测试温度为800℃时样品的电导率达到30．5S.cm^-1。与常规固相法相比，GNP法制备的样品具有更好的烧结活性和导电性能。     

An investigation of ultrasonic-assisted electrical discharge machining in gas

This study focuses on using ultrasonic to improve the efficiency in electrical discharge machining (EDM) in gas medium. The new method is referred to as ultrasonic-assisted electrical discharge machining (UEDM). In the process of UEDM in gas, the tool electrode is a thin-walled pipe, the high-pressure gas medium is applied from inside, and the ultrasonic actuation is applied onto the workpiece. In our experiment, the workpiece material is AISI 1045 steel and the electrode material is copper. The experiment results indicate that (a) the Material Removal Rate (MRR) is increased with respect to the increase of the open voltage, the pulse duration, the amplitude of ultrasonic actuation, the discharge current, and the decrease of the wall thickness of electrode pipe; and (b) the surface roughness is increased with respect to the increase of the open voltage, the pulse duration, and the discharge current. Based on experimental results, a theoretical model to estimate the MRR and the surface roughness is developed.     

COMPARISON BETWEEN THEORETICAL FORMULA AND EXPERIMENTAL RESULTS ON BUBBLE ELECTROPHORESIS

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40Cr钢电火花表面强化层的磨损特性研究

分析了在大接触应力的磨损条件下,表面残余应力和硬度对40Cr电火花强化层耐磨性的影响,探讨了其磨损机理。结果表明:滚动磨损和滚、滑动磨损时,随着试样表层硬度的提高,试样的耐磨性增大;强化层中的残余压应力可以提高强化层的硬度并增强其耐磨性。滚动磨损时,电火花强化层的磨损方式主要为粘着磨损、疲劳磨损和磨粒磨损三种机制;在滚、滑动磨损时,除上述三种机制外,还发生了氧化磨损。