Mechanism of Cellular Precipitation of Alloy Carbides and Nitrides in Multi-component Alloy Systems

多组分合金体系中合金碳化物和氮化物的胞状沉淀机理

基本信息

批准号：
62460192
负责人：
KIKUCHI Makoto
金额：
$ 5.44万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

1. Nitrogen Analysis by Electron Probe Microanaiyzer:A method of nitrogen analysis was established for solution nitrogen in Cr-Ni austenitic steels in a concentration range between 0 and 1 wt% with an accuracy of 0.01 wt%. Seven calibration curves for nitrogen were determined in austenitic steels with different Cr, Ni and Mo concentrations. A newly developed dispersion element designed for nitrogen analysis was employed.2. Nitrogen Concentration Profiles in both Untransformed Matrix and Cell: Nitrogen concentration profiles in both untransformed matrix and cell in a 25Cr-2ONi-0.59N austenitic steel aged at 800ﾟC were experimentally measured in terms of the newly established method described the previous section. It was directly confirmed that nitrogen flows into cell through a long range diffusion from the untransformed matrix to the cell, accompanying with the cell growth.3. Model for a Growth Mechanism of Cellular Precipitation in Multi-Component Systems: A model, developed by Hillert to explain growth features for the cellular precipitation in substitutional binary systems, has successfully been extended to a multi-component system involving both substitutional and interstitial alloying elements. Our model explains apparently unusual growth features of the cellular precipitation of Cr_2N in high nitrogen Cr-Ni austenitic steels. The long range diffusion of nitrogen described in the previous section reduces the driving force for cell boundary migration. This reduction of migration rate of the cell boundary leads to chromium diffusion ahead of the migrating boundary, which in turn further reduces the driving force for the cell boundary migration.

1。通过电子探针Microanaiyzer进行的氮分析：在Cr-Ni奥氏体钢中建立了一种氮分析方法，在0到1 wt％的浓度范围内，精度为0.01 wt％。在具有不同Cr，Ni和MO浓度的奥氏体钢中测定了氮的七个校准曲线。采用了用于氮分析的新开发的分散元件。2。未经转化的基质和细胞中的氮浓度谱：在未转换的基质和细胞中，在25CR-2ONI-0.59N的未转化基质和细胞中均以800°C时在800 c处老化的奥氏体钢的氮浓度谱图，以新成立的方法进行了实验测量。直接证实，氮通过从未转化的基质到细胞的远距离扩散流入细胞，并带有细胞生长3。多组分系统中细胞降水的生长机制的模型：由Hillert开发的模型，旨在解释替代二元系统中细胞沉淀的生长特征，已成功扩展到涉及涉及物质和间质合金元件的多组分系统。我们的模型解释了CR_2N的细胞沉淀在高氮CR-NI奥氏体钢中的细胞沉淀的显然异常生长特征。上一节中描述的氮的远距离扩散减少了细胞边界迁移的驱动力。细胞边界的迁移速率的降低导致铬扩散在迁移边界之前，进而进一步降低了细胞边界迁移的驱动力。