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研究了0—1.5%Nb对25kg真空感应炉冶炼的W3M02Cr4V钢(%:0.8~1.1C、3.8~4.1Cr、2.9-3.2W、1.8-2.1Mo、1.0-1.3V)组织和力学性能的影响。试验结果表明:随着Nb含量提高,铸态组织中铌碳化物增多;淬火奥氏体晶粒变细;1180℃淬火时,1.2%-1.5%Nb钢比≤0.1%Nb钢HRC值提高了6.0;二次硬化能力和红硬性也得到了提高;使钢在较高淬火温度下的机械性能得到改善。 相似文献
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研究与分析不同金相组织的QT450-10铸态所对应的机械性能。分析表明,对QT450-10铸态机械性能影响最大的因素是球铁的石墨形态,当QT450-10铸态石墨球化级别为1~4级时,其机械性能合格,大于4级,则机械性能不合格。 相似文献
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采用扫描电镜分析,硬度测试和摩擦性能测试等手段,研究了稀土对低合金耐磨铸钢组织和性能的影响。结果表明,在低合金耐磨铸钢中添加0.15%稀土,可细化合金铸态组织,增加铸态组织中的铁素体数量,减少珠光体数量,同时可细化热处理后合金的贝氏体组织,使铁素体形态和大小分布均匀,马氏体数量减少。添加稀土后可使铸态合金硬度提高9.4%,摩擦系数由0.136 9减小为0.081 9。 相似文献
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《烧结球团》2004,29(4):54-54
港口2 0 0 4年1~4月2 0 0 3年1~4月块矿粉矿球团总计块矿粉矿球团总计Dampier 70 461 4692 -2 1 73 880 861 42 75 -2 2 3 61PortHedland 773 1 1 8480 -2 62 1 1 641 2 1 5 2 43 -2 1 65 5PortWalcott 42 73 1 0 3 40 -1 461 3 3 6847881 -1 1 5 64Esperance 75 5 946-1 70 45 40 699-1 2 3 9YampiSound -1 96-1 961 3 3 --1 3 3Geraldton 1 5 95 6-2 1 5 ----PortLatta --2 92 2 92 --3 643 64Wyalla -45 -45 --8686其它0 --0 1 0 484-1 88总计1 99644 475 82 92 65 0 1 41 895 93 81 82 45 0 5 75 902004年1~4月澳大利亚各港口铁… 相似文献
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采用OM、XRD、EDS及宏观硬度测试等手段研究了真空吸铸和离心铸造方式下QAl10-4-4铝青铜的组织演变规律。结果表明,两种铸造方式下组织中相的种类、析出顺序及初始析出温度有较大的不同。真空吸铸条件下,接近铸态的组织由α相、β’相、KⅡ和KⅢ相构成,其相的析出顺序为KⅡ→α→KⅢ;离心铸造条件下,接近铸态的组织中还含有KⅠ和KⅣ相,其相的析出顺序为α+KⅠ→KⅡ→KⅣ→KⅢ,对应的相初始析出温度整体高于真空吸铸,且α相的初始析出温度远高于真空吸铸。KⅠ相的析出与合金中Fe的含量及Fe/Ni值有关,两者越高,越容易析出KⅠ相。两种铸造方式下,随着淬火温度的降低,合金的硬度在整体上均呈现先快速降低后趋于稳定的趋势。但是,真空吸铸样品在淬火温度大于900℃时出现脆化。β→α+KⅢ共析分解对合金的硬度无明显影响。 相似文献
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Si3N4-hased ceramics exhibit excellentproperties such as high strength, high corro..sion resistance, high fire resisting property andhigh thermal shock resistance. However, up tonow, the application of St3N4-based ceramicsis still limited by their poor ductility, lowtoughness and stability. Adding fiber or whisher into ceramic matrix is a useful tougheningmethod, but fiber and whisker are costly and itis difficult to homogenize them in ceramic matrix. Furthermore, ceramic powders can not fill… 相似文献
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采用三溴偶氮胂分光光度法,以盐酸分解含单一或混合轻稀土镧、铈、镨、钕和中稀土钐、钆的镁基合金,25 mL溶液中0.6 g/L显色剂用量为3~8 mL,盐酸浓度为0.5~1.0 mol/L,在640 nm波长下测定了镁基合金中的稀土总量。基体镁对测定无干扰。轻、中稀土总量的质量浓度在0.2~0.8 μg/mL范围内与吸光度呈线性,相关系数R2在0.999以上,表观摩尔吸光系数εRE为(1.10~1.19)×105 L·mol-1·cm-1。按照实验方法测定各类稀土镁合金样品中稀土总量,结果的相对标准偏差(RSD,n=6)不超过1.6%;并与电感耦合等离子体原子发射光谱法(ICP-AES)测定结果相一致。 相似文献
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《中国稀土学报(英文版)》2022,40(6):958-964
Two phosphorylcarboxylic acids, 3-((bis(2-ethylhexyloxy))phosphoryl)propanoic acid (PPA) and 3-((bis(2-ethylhexyloxy))phosphoryl)-3-phenylpropanoic acid (PPPA), were synthesized for separating yttrium from other rare earths in the chloride feed of ion-adsorption type rare earth concentrate. The effect of the factors such as pH1/2, temperature, saponification degree and phase modifiers was investigated. The separation efficiencies of PPA and PPPA are obviously better than the typical extractants such as sec-octylphenoxy acetic acid (CA-12) and naphthenic acid (NA). The extraction process of rare earths by PPA and PPPA is a cation exchanging reaction, which is similar to those of CA-12 and NA. The loaded rare earths in both PPA and PPPA systems can be effectively back-extracted by 0.5 mol/L HCl or higher concentration. A cascade extraction process for separating yttrium from other rare earths was developed using PPPA as the extractant. The yttrium product with the purity of 97.20 wt% was obtained by 35 stages of extraction and 12 stages of scrubbing. 相似文献
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Effect of rare earths on mechanical properties of plasma nitrocarburized surface layer of 17-4PH steel 总被引:1,自引:1,他引:0
The aim of this investigation is to reveal the influence of rare earths(RE) addition on mechanical properties of plasma nitrocarburized 17-4PH steel.The nitrocarburized layers were characterized by optical microscope,scanning electron microscope equipped with energy dispersive X-ray analyzer,X-ray diffractometer,microhardness tester and pin-on-disc tribometer.The results showed that RE atoms could diffuse into the surface layer of 17-4PH steel plasma nitrocarburized at 500 °C for 4 h and did not change the ... 相似文献
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Rare earth compounds as modifiers used widely in modern friction materials can enhance the interracial binding of constituents of materials and improve the comprehensive properties of materials evidently. However, there are still few reports on application of rare earth in automotive friction materials. In order to study the effect mechanism of rare earths in friction materials, a rare earth compound was selected as additive and the effects of materials doped with or without rare earth on friction and wear properties of materials were studied. The microstructure and worn surface morphology were observed by scanning electron microscopy and the macro performance was discussed. Worn surface element constitution of materials was analyzed by energy dispersive spectroscopy. Effect mechanism of rare earths on friction and wear behaviors of friction materials were discussed. The results show that doping rare earths in friction materials can stabilize friction Coefficient, lower the wear rate of materials and increase the impact strength of materials. The flexibility and fracture resistance of materials is greatly improved. Worn surface of materials doped with rare earth is compact and the surface adhesion is greatly enhanced. 相似文献
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研究了P204从富集稀土磷酸溶液中稀土元素钇、镧、钕的萃取行为,并考察了初始水相中P_2O_5浓度、萃取相比、萃取剂浓度、萃取时间对稀土萃取效果的影响。结果表明,低磷酸浓度、较大相比、较高萃取剂浓度和较长萃取时间有利于萃取稀土,并得到了萃取优化条件:初始水相中P_2O_5浓度10%、萃取相比V_0/V_1=3/1、萃取时间15min、P204浓度30%,在室温下萃取钇、镧、钕3种稀土,单级萃取率均可达到90%以上。 相似文献