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在分析铝合金温挤压用润滑剂的基础上,实验研究了不同温度下钛白粉的润滑效果.结果表明,钛白粉在铝合金温挤压成形中具有一定的润滑作用.在350℃下摩擦系数最小,可是润滑效果仍然没有石墨的理想.使用钛白粉代替石墨作为铝合金的润滑剂的设想暂时行不通. 相似文献
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基于板料成形时法兰区周向收缩、厚向增厚的特点和温成形的环境,针对铝合金板温成形过程拉深筋部位摩擦系数的测量,研制了一套新型摩擦测试装置.探讨了压边力、成形温度、润滑状态三种工艺参数和铝合金板试样楔形角对拉深筋部位摩擦系数的影响.研究表明,成形温度和润滑剂对摩擦系数影响比压边力明显;当不采用润滑剂时,随着成形温度从室温上升到250℃,摩擦系数有明显的增加;在高温状态下,三种润滑剂的使用,都可以大大降低温成形时的摩擦系数,但这三种润滑剂之间的润滑效果差异并不明显;在不同楔形角的铝合金试样成形过程中,拉深筋部位的摩擦系数随着角度的增大而增大. 相似文献
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采用挤压铸造技术制备不同粒径石墨颗粒增强的40%SiC/5%Gr/Al复合材料,研究了石墨颗粒对摩擦系数和磨损率的影响.结果表明,随着石墨的加入,复合材料的摩擦系数降低,磨损抗力提高170~340倍.另外,石墨颗粒粒径的增加也导致磨损抗力的提高,这是由于在干摩擦的过程中形成由铁的氧化物、石墨及SiC等组成的具有润滑性质的薄膜. 相似文献
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润滑条件对铝合金筒体凸台侧向挤压成形有着重要影响。通过润滑条件对成形等效应变及凸模载荷影响的模拟、分析得出:当摩擦因数增大时,等效应变、筒壁变形和凸模平均载荷值增加,但凸模载荷波动减小。综合分析后确定:当摩擦因数为0.25时,具有较好的挤压效果。水基石墨润滑剂较适合于铝合金的等温挤压,为获得该摩擦因数,制取5种不同石墨含量的润滑剂,通过摩擦试验分析,确定摩擦因数。试验结果表明:当石墨含量为质量分数18%时,该润滑剂的摩擦因数为0.25,此配比较适合于铝合金筒体凸台的侧向挤压成形。 相似文献
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目的 研究微织构纳米固体润滑剂及碳纳米管(CNTs)添加剂对微织构表面高温润滑性能的影响.方法 采用YLP-HP-1-100-100-100型光纤激光器在Cr4M04V高温轴承钢表面进行织构化处理,并填充二硫化钼(MoS2)-聚酰亚胺(PI)和不同碳纳米管添加含量的MoS2-PI-CNTs复合固体润滑剂.在环-盘接触的MMU-10G高温摩擦磨损试验机上进行了环境温度从室温到400℃的滑动摩擦性能试验.结果 填充含纳米MoS2的复合固体润滑剂的微织构表面的摩擦系数比填充含相同含量微米MoS2的低35%左右.微织构纳米MoS2-PI自润滑表面摩擦系数随碳纳米管含量的增加先减小后增大,当碳纳米管质量分数为6%时,其摩擦系数最小,且比无碳纳米管的低37%左右.在MoS2-PI纳米复合润滑剂中添加6%碳纳米管后,MoS2-PI-CNTs纳米复合润滑剂具有更高的使用温度和更低的摩擦系数.结论 纳米MoS2的润滑效果优于微米MoS2,碳纳米管有利于提高MoS2-PI复合固体润滑剂的耐热性能和润滑减摩性能. 相似文献
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Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
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. 相似文献
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After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
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. 相似文献
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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). 相似文献
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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. 相似文献
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Tang Dynasty 《中国铸造》2014,(4):I0002-I0003
<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 相似文献
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《中国铸造》2014,(5):464-466
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. 相似文献
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《机床与液压》2014,(12)
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- 相似文献
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Y. Wang H.Z. Li C.N. Yu G.M. Wu I. Gordon P. Schattschneider O. Van Der Biest 《金属学报(英文版)》2007,20(3):167-170
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. 相似文献
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A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING 总被引:2,自引:0,他引:2
W.X. Yao 《金属学报(英文版)》2007,20(1):65-71
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. 相似文献