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121.
《Materials Research Bulletin》2006,41(6):1127-1132
Microwave dielectric ceramics of tungsten–bronze-type BaSm2Ti4O12 were prepared by doping CuO (up to 2 wt.%) as the liquid-phase sintering aid. The effects of CuO additive on the densification, micro structure and dielectric properties were investigated. Due to the liquid-phase effect, the sintering temperature of BaSm2Ti4O12 ceramics with 1 wt.% CuO addition can be effectively reduced to 1160 °C, about 200 °C lower than that of pure BaSm2Ti4O12 ceramics, while good microwave dielectric properties of ɛr = 75.8, Q*f = 4914.6 GHz and τf = −7.65 ppm/°C were still achieved. 相似文献
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123.
Microstructure and abrasion wear behavior of Ni-based laser cladding alloy layer at high temperature 总被引:1,自引:0,他引:1
Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21 +20% WC+0. 5 % CeO2, Ni25+20 % WC+0. 5 % CeO2 and Ni60 + 20 % WC + 0. 5 % CeO2, the experimental results show that Ni21 + 20 % WC + 0.5?O2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature. 相似文献
124.
LEIJingguo HUANGJinliang LIUPing JINGXiaotian ZHAODongmei ZHIXiao 《武汉理工大学学报(材料科学英文版)》2005,20(1):21-24
The interaction between precipitation and recrystallization and its effect on the properties of the Cu-Ni-Si-Cr alloy during aging were discussed. The results show that the deformation results in much more dispersed precipitation of the phases. The precipitations have accelerating or retarding effects on the recrys allization. On the formation and growth of recrystallization, the precipitated phases are coarsed or dissolved in front of grain boundaries following a re-precipitation in the recrystallization area. 相似文献
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126.
苏娟华 《武汉理工大学学报(材料科学英文版)》2003,18(4):50-53
1 IntroductionTheCu Cr Zralloysarewidelyusedinavarietyofproductsrequiringacombinationofhighmechanicalprop ertiesandgoodelectricalconductivity .Examplesincludeelectronicconnectors ,integratedcircuitleadframesandweldingelectrodetips[1-4] .Howeveritisdifficulttofur therimprovetheirelectricalandmechanicalpropertiesun derconventionalsolutionheat treatment (CSHT)sincethedegreeofprecipitationhardeninguponagingisre strictedbythelimitedsolubilityofchromiumandzirconi umincopper.Inanefforttoimproveth… 相似文献
127.
Kexing Song Jiandong Xing Qiming Dong Ping Liu Baohong Tian Xianjie Cao 《Materials Science and Engineering: A》2004,380(1-2):117-122
The mechanisms responsible for the nucleation, growth and coarsening of Al2O3 particles in dilute Cu–Al alloys during internal oxidation have been investigated, and the alumina morphologies produced have been studied by electron microscopy using two-stage preshadowed carbon replica method. The alumina particle size has been observed to increase with increasing temperature of oxidation, with increasing time of oxidation, and with decreasing oxygen resource coefficient over the experimental range. These results indicate that the alumina particle size is determined by a competition between the rate of nucleation as the internal oxidation front passes and the subsequent growth and coarsening rates of the particles. 相似文献
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129.
利用ANSYS/LS_DYNA的动力学分析功能对GS3050型超高速数控锯床安全防护罩的抗冲击能力进行了数值分析,对刀具碎片侵彻有机玻璃的过程进行了数值模拟.结果表明,采用厚度为15 mm的改性丙烯酸脂有机玻璃作为GS3050锯床的安全防护罩是可靠的.数值分析和试验的结果吻合. 相似文献
130.
在自行研制的高速润滑剂拖动特性试验台上对高速航空润滑脂7018进行拖动特性的试验,得出了该润滑脂的拖动系数随速度、温度、负载的变化规律;根据试验数据推导出润滑脂的流变参数;基于修正的T-J模型,求出高速航空润滑脂7018拖动力的大小。结果表明:根据修正的T-J模型计算出的高速航空润滑脂7018的拖动系数和试验值非常接近;高速航空润滑脂7018在试验条件下表现为弹塑性,拖动系数随着滚动速度的增大而减小;当载荷小于转折载荷时,随载荷的增加拖动系数增加,当载荷大于转折载荷时,随载荷的增加拖动系数减小。 相似文献