A frequency dependent embrittling effect of high pressure hydrogen in a 17-4 PH martensitic stainless steel
A frequency dependent embrittling effect of high pressure hydrogen in a 17-4 PH martensitic stainless steel
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DOI：
10.1051/matecconf/201816503005
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
J. Sezgin;J. Yamabe
中科院分区：
文献类型：
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作者：
J. Sezgin;J. Yamabe
采用光滑圆棒拉伸试样和缺口疲劳试样研究了氢对17-4PH H1150钢拉伸性能和疲劳寿命的影响。通过在270°C下暴露于35-100 MPa氢气200 h对试样进行预充电。对于100 MPa的氢暴露，钢表现出显着的退化的延展性损失，转化为相对减少面积，RRA，为0.31。本缺口试样的疲劳寿命试验（应力集中系数为6.6）反映了长裂纹的疲劳裂纹扩展（FCG）。的疲劳极限的非充电和H充电缺口试样，定义的非扩展的长裂纹的阈值，不受氢。在较高的应力幅值，H-充电试样表现出显着的FCG加速比相比，非充电试样。虽然FCG加速度似乎存在一个上限，但该比值约为100。在较低的应力幅值下，充氢试样的断裂表面被准解理（QC）覆盖，在较高的应力幅值下，断裂表面被QC和晶间（IG）刻面的混合物覆盖。有人建议，一个周期依赖的裂纹扩展伴随着QC发生在一个较低的应力幅，而周期依赖的裂纹扩展（伴随着QC）和时间依赖的裂纹扩展（伴随着IG）的混合物，否则发生。尽管存在上限，但该混合物证明了100倍FCG加速比是合理的。
The effects of hydrogen on tensile and fatigue-life properties of 17-4PH H1150 steel have been investigated by using a smooth, round-bar specimen for tensile tests and circumferentially-notched specimen for fatigue-life tests. The specimens were precharged by an exposure to 35-100 MPa hydrogen gas at 270°C for 200 h. For the 100 MPa hydrogen exposure, the steel showed a significant degradation in ductility loss, translated by a relative reduction in area, RRA, of 0.31. The fatigue-life test of the present notch specimen (stress concentration factor of 6.6) reflects the fatigue crack growth (FCG) for long cracks. The fatigue limit of the non-charged and H-charged notched specimens, defined by the threshold of non-propagation for long cracks, was not affected by hydrogen. At a higher stress amplitude, the H-charged specimen showed a significant FCG acceleration ratio compared to the non-charged specimen. Although, an upper bound of the FCG acceleration seemed to exist, this ratio was approximately 100. The fracture surface of the H-charged specimen was covered with quasi-cleavage (QC) at a lower stress amplitude and with a mixture of QC and intergranular (IG) facets at higher stress amplitudes. It has been suggested that a cycle-dependent crack growth accompanied by QC occurs at a lower stress amplitude, whereas a mixture of cycle-dependent crack growth (accompanied by QC) and time-dependent crack growth (accompanied by IG) occurs otherwise. This mixture justifies the 100 times FCG acceleration ratio in spite of the existence of the upper bound.