共查询到18条相似文献,搜索用时 78 毫秒
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铁基合金马氏体的形核与长大SCIEI 总被引:2,自引:1,他引:2
本文使用光学和电子显微镜低温台对Fe-Mn-C合金中ε马氏体的形成过程和Fe-Ni-C合金中蝶状、透镜状、薄片状和复片状马氏体的形成过程进行了原位观察。本文实验结果指出;ε马氏体由4—5个层错重叠形成,证实了Olson和Cohen提出的层错化模型;薄片状马氏体优先在晶界和三角晶界处形核,初始长大形态(表面浮突)为细针状;观察到透镜状马氏体由薄片状向两侧加厚而形成,提出了相变孪晶长大受阻时,半共格孪晶界面位错可经位错分解反应发射出a/2[111]b=a_0/2[101]_f全位错,提供薄片状马氏体由孪生切变向滑移切变转换所需的位错源。 相似文献
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刘宗昌等学者近几年相继在国内杂志发表了有关马氏体相变非切变机制的论文,并将这些论文作为他们2012年出版的《马氏体相变》一书中的主要创新内容予以强调。他们否定已被国际公认的马氏体相变切变机制的主要依据有两条:1)马氏体相变切变机制缺乏实验基础,即缺乏现代实验技术,如透射电镜(TEM),原子力显微镜(AFM)的实验证明;2)根据他们的计算,马氏体切变能太大,相变驱动力无法克服切变能。本文作者首先结合马氏体晶体学表象理论(PTMC)给出论证马氏体相变切变机制的TEM和AFM实验;随后介绍徐祖耀提出的计算马氏体相变切变能的方法;最后评论刘宗昌等的论断和切变能的计算方法。 相似文献
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β—Cu基合金马氏体相变热力学 总被引:1,自引:0,他引:1
提出对β-Cu基合金热弹性马氏体相变的热力学处理。计算了Cu-Zn,Cu-Al及Cu-Zn-Al合金马氏体相变驱动力,T_0温度及M_s温度,M_s的计算值与实验值符合很好。母相有序降低Cu-Zn和Cu-Zn-Al的M_s,但升高Cu-Al的M_s(T_0)。并简介了两种估算非化学自由能的方法。 相似文献
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球铁铸态试样与热处理态试样的彩色金相制备工艺规范不同。分析了热处理态试样难于成色的原因,并试验得出热处理态彩色金相制备工艺规范。通过彩色金相图对马氏体球铁磨球的结晶形态和晶内缺陷进行了深入讨论。结果表明,彩色金相比黑白金相能揭示更多的马氏体结构特征信息,并为保证获得力学性能良好的球铁提供依据。 相似文献
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马氏体相变的动态观察 总被引:3,自引:1,他引:2
用Cu-l4Al-4Ni(wt.-%)记忆合金粗大单晶,在光学显微镜上配上偏光、干涉、相衬等附件,使不同取向的马氏体显示出不同的色彩,研究了马氏体→母相及母相→马氏体的动态转变过程,发现马氏体相变过程的形式不是单一的,并显示了一些鲜为人知的、马氏体相变过程的细节。 相似文献
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通过显微硬度测量和X射线衍射结构分析,研究了化学镀Fe-Mo-B非晶态合金、Fe-W-B晶态合金镀层的显微硬度随成分、热处理及结构的变化关系。结果表明:两合金系的显微硬度均随类金属B含量增加而提高,电子浓度的变化规律则相反。且热处理过程中,随退火温度增加,Fe-W-B合金镀层的显微硬度出现峰值,这与晶化析出相的类型及数量有关。 相似文献
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ZHANG Xiumu LI Yiyi Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1991,4(6):407-413
In situ observations of the nucleation and growth of ferrous martensites,including ε-, lenticular,butterfly,thin-plate and composite-plate ones at low temperature stage on optical or transmission electron microscope were carried out.The results confirmed the faulting model for the formation of ε-martensite proposed by Olso and Cohen.The grain boundaries and tri- ple points are the favourable nucleation sites for the thin plates,and their surface relief grown initially like a small needle.The lenticular martensite was observed as two stages of formation.According to the dislocation resolving reaction. (a/6)[111]_b→(a/3)[]_b+(a/2)[111]_b,the emission dislocation(=(a/2)[111]_b)acting as the dislocation source for the transition of lattice invariant shear from twinning to slip was proposed. 相似文献
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GONG Hai ZHANG Weiyi Dalian Railway Institute Dalian ChinaZHANG Xiumu Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1991,4(6):426-430
Martensites distributed along the austenite grain boundaries and twin boundaries have beenexamined in Fe-C,Fe-Ni-C and Fe-Cr-Mn-Mo-C alloys.The martensites may nucleatepreferentially and grow easily along these boundaries.In the mixed martensites,thepreferentially formed one is plate or butterfly martensite 相似文献
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ZHONG Jiaxiang QI Yan Beijing Institute of Technology Beijing ChinaZHANG Xiumu GUO Yunyi Institute of Metal Research Academia Sinica Shenyang China Beijing Institute of Technology Beijing China 《金属学报(英文版)》1991,4(2):86-90
A new “mid-relief” plate martensite was observed together with lenticular plate and thin plate martensites in Fe-29.37Ni-0.34C alloy after twice stepped cooling:-100/-120℃, -120/-140℃,-155/-165℃ and -165/-196℃,by means of colour metallography and TEM.The morphology of martensites changes with decreasing M_s temperature.The “mid-relief” plate martensite is characterized by the intensive mid-relie and the substructures of symmetric double twins or half twins and half dislocations,the formation of this martensite can be interpreted by a stress-induced co-generated mechanism. 相似文献
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《中国有色金属学会会刊》1998,(3)
1INTRODUCTIONBesidessteels,nonferousmetalssuchasaluminium,copper,titaniumandtheiraloysareveryimportantmaterials,duetotheira... 相似文献
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含硫油品储罐腐蚀产物硫化亚铁自燃性的研究 总被引:11,自引:1,他引:11
模拟油品储罐中硫化亚铁的生成方式,研究了H2S气体在没有氧气存在的条件下与油品储罐内壁腐蚀产物-Fe(OH)3、Fe2O3和Fe3O4发生反应及反应产物硫化亚铁的自燃性.结果表明:油品储罐中腐蚀产物Fe(OH)3、Fe2O3和Fe3O4与H2S在无氧条件下均可发生放热反应生成硫化亚铁,且生成的硫化亚铁与空气接触会发生氧化反应放出热量,热量聚集使油品温度上升是引起油品自燃并导致油品储罐发生火灾和爆炸事故的主要原因.但不同生成方式所生成的硫化亚铁的氧化速度不同,其自燃性也不同. 相似文献
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SUN Jialin Kunming Institute of Technology Kunming ChinaKANG Mokuang Northwestern Polytechnical University Xi''''an China 《金属学报(英文版)》1991,4(6):458-461
Based on the TEM analysis of substructures of lower bainite in two steels containing Si,thelattice invariant shear elements were determined and a plastic accommodation double-shearmodel of phenomenological crystallography was proposed.The theoretical predictions aboutcrystallography given by the model are in good agreement with the experimental data for thesteels tested. 相似文献