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Grain refinement of superalloy K4169 was achieved by adding refiners into the alloy melt and their effects on the mechanical properties were investigated. The tensile properties at room temperature and 700℃ and low cycle fatigue properties at room temperature were compared for both conventional and fine grained test bars.The results indicate that the rupture strength, yield strength, elongation and reduction of area for refined grains are all much superior to those for coarse ones. Whereas the elongation and reduction of area of fine grained samples decrease at 700℃. Low cycle fatigue properties of samples with refined grains at room temperature are improved significantly. In addition, the degree of dispersion of low cycle fatigue data of samples with refined grains is diminished. 相似文献
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1 INTRODUCTIONAgreatamountofpracticeprovesthat ,aftertheoriginalchargesareremelted ,themeltstatehashereditaryeffectsonthesolidificationstructurenewlyobtained .Hereditycanbeconsideredfrom generalsenseasthetransformationofthesimilaritiesinthestructureorphysicalpropertiesfromtheoriginalob jectstothesecondaryones .Moreover ,itissuitablefordescribingpropertiesthatcorrelatewiththepro cesswhichthealloysamplesexperiencedinsteadofpropertiesofalloystatefunctions .Whilestudyingthestructuralheredity… 相似文献
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用粉末冶金工艺制备了一种改性的锆石墨类吸气剂,研究了激活工艺和吸气剂表面气体压强对该吸气剂吸气性能的影响。结果表明:该类吸气剂具有优越的室温吸气性能。高温短时间的激活效果优于低温长时间。增加吸气剂表面气体压强Pg有利于提高吸气剂的吸气速率和吸气量,且适当增加Pg比提高激活温度更有利于提高吸气剂的吸气性能。本文从吸气剂对气体分子的吸附和扩散作用机理解释了上述结果。 相似文献
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镀Al空心玻璃微球/Ni-Zn铁氧体/环氧树脂复合材料的吸波性能研究 总被引:1,自引:1,他引:0
利用磁控溅射的方法对空心玻璃微球表面镀Al,研究了由镀Al空心玻璃微球/Ni-Zn铁氧体制成的复合材料在雷达波频段范围内的电磁特性,利用模型计算了所制备样品的微波反射率,并与实测反射率进行对比。结果表明,随着镀Al空心玻璃微球含量的增加,复合材料介电常数实部,虚部均增加,而磁导率的实部和虚部均减小;计算反射率数值与实测数值基本相吻合。由此可见,通过改变镀Al空心玻璃微球和Ni-Zn铁氧体的比例,可以调节电磁参数,提高材料的吸波性能。 相似文献
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1IntroductionIn the field of gas examination,selectivity,sensitivity andresponse speed are thei mportant parametersfor gas sensors.Semiconductor with gas sensitivityis beneficial for the micromation andintegration of gassensors,whichis suitable for the ICindustry.At present,a N-type semiconductor oxide-SnO2fil m with a broadforbidden bandis widely usedinthegas sensors.For the gas sensors using semiconductor oxides,surface modificationis an effective waytoi m-prove their gas sensitivity[1].P… 相似文献
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本文用x射线光电子能谱仪(XPS)对TiZrV合金吸气剂的激活过程进行了监测,研究了吸气剂表面Ti、Zr、V、 O、 C元素的化学价态随温度的变化.实验结果表明:暴露过大气的TiZrV吸气剂表面的Ti、Zr和V主要以氧化态的形态存在.当吸气剂置于高真空激活时,钒的氧化物在较低的温度(250℃-300℃)开始被还原,钛的氧化物在稍高于钒的温度(300℃)也开始被还原,400℃时表面已经有大量的金属钛的存在,而Zr的氧化物在(100℃-400℃)激活过程中,则没有明显的变化. 相似文献