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为从微观角度研究氢原子对α-铁力学行为的影响,并解释α-铁在形变过程中材料微结构演化的细节与规律,采用分子动力学模拟方法研究在拉伸载荷下,氢浓度对含有对称斜晶界的双晶α-铁裂纹扩展的影响。计算结果表明:双晶α-铁的峰值应力随着氢浓度的增加而减小。由于左右裂纹晶向的不同,致使裂纹不对称的开裂。研究发现,氢原子会阻碍裂纹扩展,但氢原子对左右裂纹阻碍的机制不同。研究结果显示,氢原子聚集在左裂纹尖端,增强裂纹尖端区域的局部塑性,阻碍裂纹向左侧的扩展;然而,裂纹右侧区域的氢原子不仅增强裂纹尖端的局部塑性,还促进Hirth位错在右裂纹尖端相变区域的成核,从而有效阻碍右裂纹扩展。
In order to study the effect of hydrogen atoms on the mechanical behavior of α-iron from a microscopic point of view, and to explain the details and laws of the microstructure evolution of α-iron during deformation, molecular dynamics simulation was used to study the effect of hydrogen concentration Effect of twinning α-iron crack growth on the symmetrical oblique grain boundaries. The calculation results show that the peak stress of α-iron double crystal decreases with the increase of hydrogen concentration. Due to the different orientation of cracks around, resulting in crack asymmetry cracking. The study found that hydrogen atoms will hinder the crack growth, but hydrogen atoms on the left and right cracks different mechanisms. The results show that hydrogen atoms accumulate at the tip of the left crack and enhance the local plasticity in the crack tip region, which hinders the crack propagating to the left. However, hydrogen atoms in the right crack region not only enhance the local plasticity at the crack tip, but also promote Hirth dislocation Nucleation at the right-crack tip phase transition region effectively hinder the right crack propagation.