Thermomechanical and Isothermal Fatigue Behavior of 316LN Stainless Steel with Varying Nitrogen Content
Thermomechanical and Isothermal Fatigue Behavior of 316LN Stainless Steel with Varying Nitrogen Content
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DOI：
10.1007/s11661-014-2653-y
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发表时间：
2015-02
期刊：
影响因子：
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通讯作者：
G. V. Prasad Reddy;A. Nagesha;R. Sandhya;S. Sankaran;M. D. Mathew;K. Bhanu Sankara Rao
中科院分区：
文献类型：
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作者：
G. V. Prasad Reddy;A. Nagesha;R. Sandhya;S. Sankaran;M. D. Mathew;K. Bhanu Sankara Rao
本文介绍了含0.07、0.14和0.22 wt pct氮的316LN不锈钢的热力学（TMF）和等温（IF）疲劳行为。在温度循环范围为573 K至873 K（300°C至600°C）的TMF测试中，随着氮含量的增加，相内（IP）和相外（OP）循环的寿命都下降了，峰值在0.07 wt pct N。相比之下，在873 K（600°C）进行中频循环时，0.14 wt pct N产生了最大寿命。循环寿命遵循IP-TMF < IF < OP- tmf循环的顺序，并且与316LN SS中的氮含量无关。尽管OP循环的循环应力响应较高，但IP-TMF循环的寿命比OP循环的寿命低2至2.5倍。在本研究的所有氮含量中，氮和动态应变时效在IP和OP-TMF中均以平面滑移带的形式诱导滑移局部化，而IF变形仅在0.22 wt pct n时出现完全的平面滑移模式。滑移带密度增加，带间间距减小)，再加上高拉伸循环应力，破坏了氮含量对TMF寿命的有益影响。
Thermomechanical (TMF) and isothermal (IF) fatigue behavior of 316LN stainless steel alloyed with 0.07, 0.14, and 0.22 wt pct nitrogen is presented in this manuscript. In the TMF tests with temperature cycling in the range of 573 K to 873 K (300 °C to 600 °C), life decreased with increasing nitrogen content for both in-phase (IP) and out-of-phase (OP) cycling, with a peak at 0.07 wt pct N. In contrast, 0.14 wt pct N yielded maximum life under IF cycling carried out at 873 K (600 °C). Cyclic lives are seen to follow the sequence, IP-TMF < IF < OP-TMF cycling, and it remained same irrespective of the nitrogen content in 316LN SS. Lives under IP-TMF are lower than those in OP cycling by a factor of 2 to 2.5, in spite of the higher cyclic stress response in OP cycling. At all the nitrogen contents in the present study, nitrogen and dynamic strain aging induced slip localization in the form of planar slip bands both in IP and OP-TMF, in comparison to IF deformation wherein complete planar slip mode of deformation is evidenced only at 0.22 wt pct N. In TMF studies, increasing nitrogen content promoted strong slip localization (i.e., increase in slip band density with a decrease in interband spacing) in combination with high tensile cyclic stresses that marred the beneficial effect of nitrogen content on TMF life.