Detection and evaluation of material degradation of thermally aged duplex stainless steels: electrochemical polarization test and AFM surface analysis
Detection and evaluation of material degradation of thermally aged duplex stainless steels: electrochemical polarization test and AFM surface analysis
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DOI：
10.1016/0022-3115(96)00361-3
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发表时间：
1996-07
影响因子：
3.1
通讯作者：
Yongsun Yi;T. Shoji
中科院分区：
文献类型：
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作者：
Yongsun Yi;T. Shoji
采用夏比冲击试验和显微硬度测试对铸态双相不锈钢的热时效脆化进行了评价。为了无损评价铸态双相不锈钢的热时效脆化，在0.1 M硝酸溶液中对服役暴露材料和实验室时效材料进行了电化学极化测量，并利用原子力显微镜（AFM）测量了极化测量过程中的溶解深度。在极化曲线中，所有试样的峰值电流密度均出现在电流的负范围内，且时效材料的峰值大于未时效材料。随着时效时间的延长，奥氏体相的溶解深度没有变化，而铁素体相的溶解深度随时效时间的延长而增加，这与极化结果一致。AFM测定的溶解深度与材料力学性能的变化具有良好的相关性，并在此基础上提出了双相不锈钢热时效脆化的评价方法。
Thermal aging embrittlement of cast duplex stainless steels was evaluated by Charpy impact test and microhardness measurement. Also, for the purpose of the non-destructive evaluation of thermal aging embrittlement in cast duplex stainless steels, electrochemical polarization measurements for service exposed and laboratory aged materials were carried out in 0.1 M nitric acid solution and the depth of dissolution during the polarization measurement was measured with an atomic force microscope (AFM). In the polarization curves, the peak current densities of all specimens tested were appeared in the negative range of current and aged materials showed larger peak values than unaged ones. In the dissolved depth of austenite phase, no trend can be seen with aging time but those of ferrite phase were increased according to aging time, which has the same tendency as the polarization results. A good correlation between the dissolved depth measured by the AFM and the changes in mechanical properties of materials and, based on these results, an evaluation method for thermal aging embrittlement of duplex stainless steels was suggested.