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本实验室建立了研究热轧辊磨损过程的一种模拟装置,本装置共有以下特点:1.实验条件接近于实际热轧条件;2.试验材料的消耗可以减少到最低限度;3.被研究的磨损试样(辊面工作部位)能直接放进扫描电镜中观察。试验结果表明,本试验室所采用的模拟装置并配合扫描电镜原位观察技术是研究热轧条件下辊面磨损过程的一种有效方法。 相似文献
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放电等离子烧结不同粒径匹配的WC-Co混合粉末 总被引:1,自引:0,他引:1
采用一种包括混合粉末真空预处理和放电等离子烧结(SPS)的新型烧结技术,制备超细晶WC-10Co硬质合金块体。采用场发射扫描电镜观察硬质合金的形貌和晶粒组织,采用三点弯曲法测量试样的断裂强度,利用显微硬度仪测量维氏硬度HV30且据此估算试样的断裂韧性KIC,并与真空烧结和直接SPS试样进行对比,同时还研究初始粉末中WC粉与Co粉的粒径匹配对SPS块体的显微组织和力学性能的影响。结果表明,与真空烧结和直接SPS相比,此种方法制备的WC-10Co合金晶粒细小、组织均匀,具有优异的综合力学性能,尤其是强度明显提高,硬度为1608HV30,断裂韧性为14.0MPa.m1/2,横向断裂强度为3100MPa;WC和Co粉末的粒径匹配对SPS块体的显微组织和力学性能具有较显著的影响。 相似文献
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为了研究S31042试验用钢短时高温拉伸塑性波动大的原因,采用体视显微镜、金相显微镜、扫描电镜、透射电镜进行了断口形貌和微观组织观察分析,用X射线衍射分析了相应状态试样的萃取粉末。用Thermo-Calc热力学软件进行了相图计算。结果表明:大块簇状的含铌相颗粒分布在晶界和晶内时,固溶态S31042试验钢短时高温(700℃)拉伸塑性较低,伸长率仅28%,而且断裂试样的表面严重龟裂。当钢中的含铌相颗粒细小、独立分布时,短时高温(700℃)拉伸塑性较高,伸长率高达50%,断裂试样的表面没有龟裂。含铌相的形态是固溶态S31042钢塑性波动的原因。因此,改善含铌相颗粒的形态,有益于提高固溶态S31042钢的短时高温拉伸塑性。 相似文献
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讨论了应用粉末压片X-射线荧光光谱法测定炼钢用外购生铁中Si、Mn、P、S、As元素含量的方法。样品经钻床钻取为碎屑状,用粉碎机研磨为粉末,以硼酸作衬底,将粉末试样制成圆片状,用X-射线荧光光谱仪测定试样中多元素含量。试验证明,方法分析周期短,数据准确可靠,能提高外购生铁检验效率,同时降低采用化学法而引起的酸烟和废液对环境的污染。 相似文献
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AbstractAlthough hardmetal has been manufactured, by the powder metallurgy route for well over 55 years, the characterization of the starting powders, basically tungsten carbide and cobalt, still commands the attention of powder metallurgists. Three fine cobalt powders and two 1·2 μm (FSSS) tungsten carbide powders, freely available, have been both chemically and physically characterized. Various techniques of measuring physical characteristics, such as FSSS, BET gas adsorption, pore volume and area, sedimentation, SEM powder, and SEM polished and etched sections of copper impregnated powders, have been studied. The techniques have been discussed in relation to their advantages and disadvantages. The measurement by FSSS and BET gas adsorption give fairly reproducible results, as does the sedimentation technique. However, by reference to the two SEM techniques it has been shown that the very important characteristic of particle shape and, more importantly for tungsten carbide powder, particle agglomeration (due to the manufacturing route) is not fully revealed. The two SEM techniques are indispensable for defining shape and agglomeration characteristics. It is suggested that by using the SEM copper impregnated powder method and a semi-automatic image analysing system the true crystal (grain) size distribution of tungsten carbide powders can be evaluated. The chemical purity of cobalt and tungsten carbide powders has significantly increased in recent years. Some preliminary results from milled tungsten carbide powders are discussed. PM/0393 相似文献
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B. I. Prenitzer L. A. Giannuzzi K. Newman S. R. Brown R. B. Irwin F. A. Stevie T. L. Shofner 《Metallurgical and Materials Transactions A》1998,29(9):2399-2406
Particles of Zn powder have been studied to show that high-quality scanning electron microscope (SEM) and transmission electron
microscope (TEM) specimens can be rapidly produced from a site-specific region on a chosen particle by the focused ion beam
(FIB) lift-out technique. A TEM specimen approximately 20-μm long by 5-μm wide was milled to electron transparency, extracted from the bulk particle, and micromanipulated onto a carbon coated copper
mesh TEM grid. Using the FIB lift-out method, we were able to prepare a site-specific TEM specimen from a difficult material
in under 3 hours. The TEM analysis of the lift-out specimen revealed a large amount of thin area free from characteristic
signs of damage that may be observed as a result of conventional argon ion milling. The overall microstructure of the specimen
prepared by the FIB lift-out method was consistent with samples prepared by conventional metallographic methods. A grain size
of ∼10 to 20 μm was observed in all specimens by both TEM and SEM analysis. Light optical microscopy revealed the presence of internal voids
in ∼10 to 20 pct of all particles. The SEM analysis showed the voids to extend over ∼70 pct of the particle volume in some
cases. 相似文献
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对湿法冶金工艺制备的两种铁基预合金粉(Fe_(43)Co_(24)Cu_(33)和Fe_(56)Co_(14)Cu_(30),以下简称A和B)进行了性能研究,对其粉末颗粒的形貌和氧含量进行了对比分析,并经过750、800、850、900、950℃五种烧结温度制备热压烧结试样。通过阿基米德排水法测定烧结试样密度,利用HR-150A型洛氏硬度计测量烧结试样的显微硬度,利用三点弯曲法测定烧结试样的抗弯强度,使用扫描电子显微镜观察烧结试样的断口形貌。结果表明:随着烧结温度的提高,两种烧结试样的密度都呈增加趋势,当温度超过850℃后,密度变化逐渐趋于平缓;烧结试样的硬度都随着温度的升高先增加后降低,烧结试样B硬度在850℃以前要高于烧结试样A,且在800℃时达到最大值,当温度高于850℃时烧结试样A的硬度要高于烧结试样B;两烧结试样的抗弯强度都随温度的升高而增大;预合金粉A的烧结试样对温度敏感性较小,当温度达到850℃以后,晶粒几乎不在长大,预合金粉B的烧结试样对温度敏感性比较大,随着温度的升高,晶粒不断地长大。 相似文献
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介绍了粉末烧结内氧化银氧化锡电触头材料金相试样的制备、显微组织的观察和分析方法,并探讨了银铝合金粉末压坯烧结内氧化的过程。结果表明,金相分析方法是控制烧结内氧化工艺和产品质量的有效手段。 相似文献
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精矿稀土抛光粉制备工艺研究 总被引:9,自引:4,他引:5
采用稀土精矿为原料,研究了制备稀土抛光粉工艺过程,通过DTA、TG、XRD、SEM、物化分析等检测手段,对试制样品的结构、形貌、物化性能等进行了分析。试制的精矿稀土抛光粉抛光效果优良,制备工艺简短,成本低廉 相似文献
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