Fatigue damage in austenitic-ferritic duplex stainless steels
Fatigue damage in austenitic-ferritic duplex stainless steels
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DOI：
10.1111/j.1460-2695.1995.tb00142.x
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发表时间：
1995
影响因子：
3.7
通讯作者：
S. Degallam;A. Sedwuki;G. Degallaix;T. Kruml;J. Polák
中科院分区：
文献类型：
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作者：
S. Degallam;A. Sedwuki;G. Degallaix;T. Kruml;J. Polák
研究了两种具有天然复合材料结构和不同氮含量的奥氏体-铁素体双相不锈钢的低周疲劳损伤。两种钢都表现出初始循环硬化，随后软化和长稳定期。循环应力-应变曲线随着氮含量的增加而增加，而Manson-Coffin曲线在中等疲劳寿命处相交。对表面浮凸的研究表明，铁素体和奥氏体中都有强烈的滑移痕迹。它们的密度受氮含量的影响。铁素体中持久滑移带（PSB）标记的强度和密度都较高。发现裂纹萌生主要出现在PSB中的铁素体晶粒在低应变幅，并在铁素体和奥氏体晶粒在最高应变幅。循环应力-应变响应和疲劳寿命的水平进行了讨论的循环应变局部化和纹理和氮含量的强度和疲劳损伤的影响。与氮含量较低的钢相比，由于高氮合金化，奥氏体相的强度增加，导致铁素体中的循环滑移局部化，以及疲劳寿命的降低。
Fatigue damage in two austenitic-ferritic duplex stainless steels, with the structure of a natural composite and different levels of nitrogen content, was studied in low-cycle fatigue. Both steels show initial cyclic hardening followed by softening and a long stabilisation period. The cyclic stress-strain curve increases with the nitrogen content while Manson-Coffin curves of both steels intersect at medium fatigue lives. The study of the surface relief reveals intensive slip markings both in ferrite and in austenite. Their density is influenced by the nitrogen content. Both the intensity and density of the persistent slip band (PSB) markings are higher in the ferrite. Crack initiation was found to appear predominantly in PSBs in the ferritic grains at the low strain amplitudes, and in the ferritic and austenitic grains at the highest strain amplitudes. The level of the cyclic stress-strain response and the fatigue lives are discussed in terms of the cyclic strain localisation and of the effect of texture and nitrogen content on the strength and fatigue damage. The increased strength of the austenitic phase, due to high nitrogen alloying, results in cyclic slip localisation in the ferrite, and the decrease of fatigue life, compared with the steel with the lower nitrogen content.