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对不同铝含量超高碳钢进行了相平衡热力学计算、热处理工艺试验以及扫描电镜的微观组织观察,研究了铝对超高碳钢平衡共析转变、先共析碳化物的数量和析出行为的影响。结果表明,对超高碳钢进行铝合金化后,平衡共析转变扩展为一个温度区间(A1b~A1c),共析转变的温度下限、上限和共析转变的温度范围均随铝含量的提高而增大;铝合金化使得平衡状态下的先共析碳化物数量减少,从而抑制网状先共析碳化物形成。碳含量低于1.6wt%,添加2wt%以上的铝,可以抑制超高碳钢先共析网状碳化物的形成。在同样的冷却条件下,添加铝使超高碳钢共析体片层间距细化。 相似文献
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铝元素抑制超高碳钢中网状碳化物析出机理 总被引:4,自引:0,他引:4
借助相图计算、能谱分析及组织观察研究了铝元素对超高碳钢中网状碳化物析出过程的影响,含碳1.5wt%的超高碳钢添加不同含量的铝后显著影响网状碳化物的析出:随铝含量增加,奥氏体晶粒尺寸愈小、晶界愈多,导致网状碳化物减薄;未溶碳化物愈多、奥氏体固溶碳含量愈少,导致网状碳化物析出量减少;晶界聚集铝量增加,聚集的铝抑制碳化物的形核及长大。当铝含量接近2.0wt%时,网状碳化物出现断续,甚至有的晶界没有碳化物析出,在球化过程中,该网状碳化物很容易球化。 相似文献
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锻造超高碳钢的球化工艺与力学性能 总被引:9,自引:0,他引:9
利用碳浓度不均匀奥氏体离异共析转变机制,借助于相图计算技术,对UHCs-1.0Al(含Al 1.0%wt%)和UHCs-1.5Al(含Al 1.5wt%)两种锻造超高碳钢提出了在三相区奥氏体化并在共析转变温度低限等温球化工艺,并对不同球化组织的力学性能进行了测定。组织观察表明,含Al超高碳钢锻态组织为极细的珠光体组织,Al的添加对网状碳化物有抑制作用,两种超高碳钢经最佳的球化工艺处理后得到了碳化物弥散分布于铁素体基体的复相组织,随碳化物球化程度的提高,塑性指标显著改善。球化UHCs-1.5Al超高碳钢达到了良好的综合力学性能,σb,σs分别为1050MPa和740MPa,伸长率达到14%。 相似文献
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球化工艺对热轧超高碳钢组织性能的影响 总被引:1,自引:0,他引:1
利用离异共析原理,采用不同的热处理工艺球化热轧超高碳钢。组织观察表明:热轧预处理消除了铸态下晶界网状粗大碳化物,并获得颗粒状碳化物与片状珠光体的混合组织。球化热处理时,奥氏体化温度升高、保温时间延长,碳化物颗粒的间距增大,减缓冷却速率增加碳化物的析出。对球化后超高碳钢进行拉伸力学性能试验,850℃球化后的强度很高(σ0.2=688.71MPa,σb=1005.78MPa),屈强比和伸长率分别为0.69、16.7%。拉伸后的断口形貌分析表明,超高碳钢拉伸过程中裂纹易在大颗粒碳化物处萌生、扩展。 相似文献
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利用离异共析原理,采用不同的热处理工艺球化热轧超高碳钢。组织观察表明:热轧预处理消除了铸态下晶界网状粗大碳化物,并获得颗粒状碳化物与片状珠光体的混合组织。球化热处理时,奥氏体化温度升高、保温时间延长,碳化物颗粒的间距增大,减缓冷却速率增加碳化物的析出。对球化后超高碳钢进行拉伸力学性能试验,850℃球化后的强度很高(σ0.2=688.71MPa,σb=1005.78MPa),屈强比和伸长率分别为0.69、16.7%。拉伸后的断口形貌分析表明,超高碳钢拉伸过程中裂纹易在大颗粒碳化物处萌生、扩展。 相似文献
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研究了在真空感应炉中使用Cao坩埚熔炼镍基高温合金的脱氧效果,分析了加入0.02%C、0.5%Al对脱氧的影响。结果表明:采用CaO坩埚,选择合适的熔炼工艺及C、Al加入量,可使氧的含量降低到小于0.0006%。 相似文献
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L. Yu T. P. Hou X. L. Wang X. L. Wan K. M. Wu 《Science & Technology of Welding & Joining》2014,19(8):708-714
The fine microstructure of martensite–austenite (M–A) constituents in simulated coarse grained heat affected zone (HAZ) of high strength low alloy steel with varying aluminium content (0·038 and 0·070 wt-%) at 100 kJ cm?1 heat input welding was investigated. The result shows that M–A constituents with 0·038%Al consisted of lath martensite and retained austenite. The retained austenite was distributed along the martensite lath. Whereas, the M–A constituents with 0·070%Al consisted of lath martensite and retained austenite, as well as a small amount of twinned martensite. The amount of retained austenite in M–A constituents with 0·070%Al was becoming higher slightly than that with 0·038%Al. Accordingly, the volume fraction of M–A constituents was reduced with 0·070%Al. Appropriate aluminium addition could decrease not only the area fraction but also the size of M–A constituents, which are beneficial for improving the toughness of HAZ. 相似文献
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镍基高温合金的真空感应熔炼脱氧 总被引:1,自引:0,他引:1
研究了在真空感应炉中使用CaO坩埚熔炼镍基高温合金的脱氧效果,分析了加入0.02%C和0.5%Al对脱氧的影响,初步进行了在CaO坩埚中脱氧反应的热力学计算。研究表明:熔化期可以脱除大部分的氧;采用CaO坩埚,选择合适的熔炼工艺及C和Al加入量,可使氧的含量降低到小于0.0006%。 相似文献
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The effect of metallic aluminium powder on the production of boron carbide–alumina composite was studied. Boric acid, carbon and aluminium powders were mixed in stoichiometric ratio, ball milled and heat treated at temperatures between 1300 and 1650 °C for 1–5 h in the presence of argon flow. Depending on the ratio of boron oxide to carbon, the formation of boron carbide by the carbothermal reduction, was possible at a temperature of around 1500 °C, but with the addition of metallic aluminium to the mixture of boric acid and carbon, the carbide formation temperature was reduced at least 300 °C. At 1300 °C, B4C was the major phase with alumina in the reaction products. The liquid–solid reaction mechanism, which occurred during the aluminothermic process, had a specific influence on the formation of boron carbide. 相似文献
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The microstructure evolution in carbide strengthened Alloy 602 CA during exposure to a synthetic flue gas (N2–2.5%O2–8.6%H2O–16.4%CO2) at 1100 °C has been studied. The chromium and aluminium loss resulted in a chromium depleted alloy subsurface area and the dissolution of the carbides within this area. An increase of the carbide fraction in the sample core was observed and quantified. Phase equilibria calculations revealed that the depletion of aluminium as well as that of chromium triggers carbon to leave the depleted area. The overall carbon depletion in that area corresponded to the observed increase in carbide fraction in the sample core. 相似文献
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综合运用全自动相变仪,扫描电镜及电子探针技术研究了成分已均匀化的T7钢在珠光体转变温度范围等温所形成的先共析铁素体周围奥氏体中的碳分布。发现先共析铁素体周围存在有富碳奥氏体薄层,且此富碳奥氏体薄层中的碳分布并非都是 ;此一富碳奥氏体薄层的特征与随后转变所变形成的珠光体及马氏体形态相关。 相似文献
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The phase compositions of alloys based on Fe-40 at.% Al with additions of carbon ranging from 1.9 to 3.8 at.% and with and without the addition of 1.2 at.% Si were studied by light optical and transmission electron microscopies, X-ray diffraction and electron probe microanalysis. The structure of the matrix of all alloys is a B2 lattice, inherent to the intermetallic compound FeAl. Two main precipitating phases are observed: graphite and aluminium carbide Al4C3. The quantity of the phases depends in detail on the chemical composition and the heat treatment. The presence of Al4C3 in the alloys with the highest carbon content is in agreement with the recent theoretical prediction of a Fe–Al–C ternary phase diagram by Ohtani et al., as well as with older experiments of Vyklický and T?ma. The occurrence of Al4C3 is supported by the addition of silicon. Small traces of carbide κ of perovskite-type Fe3AlC are observed only in the alloys with the lowest aluminium and carbon contents. 相似文献
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铝及铝铁合金的加工软化机理 总被引:4,自引:0,他引:4
研究了三种纯度的铝及其Al-2%Fe合金在室温轧制状态下的加工软化行为及软化机理,试验证明:99.996%Al当轧制率为80%以上时出现加工软化现象;99.96%Al和99.6%Al不发生软化,用99.996%Al配制的Al-2%Fe合金当轧制率为60%以上时出现加工软化;用99.96%Al配制的Al-2%Fe合金当轧制率为90%以上时出现加工软化;用99.6%Al配制的Al-2%Fe合金不发生加 相似文献