Stanisławska Alicja, Moszczyńska Dorota, Mizera Jarosław, Cavaliere Pasquale, Szkodo Marek
Faculty of Mechanical Engineering and Ship Technology, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw, Poland.
Materials (Basel). 2025 Aug 18;18(16):3870. doi: 10.3390/ma18163870.
This study investigates the strain hardening and dislocation structure in the surface layers of C45 steel subjected to precision grinding at various depths. The aim was to assess how different grinding conditions influence the mechanical response and defect structure of ferrite. Nanoindentation was used to evaluate mechanical properties, while X-ray diffraction analysis provided data on the microstrain, crystallite size, and residual stress. The character and density of dislocations were further examined using modified Williamson-Hall and q-parameter analysis. The results revealed that the sample ground to a depth of 2 μm exhibited the highest density of statistically stored dislocations, as well as the lowest dislocation mobility. This condition also corresponded to the highest residual stresses and the greatest share of screw dislocations, indicating intense strain localization. In contrast, deeper grinding depths resulted in lower dislocation densities and reduced the strain energy. The observed trends highlight the formation of a dislocation-rich nanostructured layer in the shallowest ground region. These findings provide new insights into the mechanisms of surface hardening in ferritic steels and demonstrate how the depth of material removal during grinding governs the subsurface microstructure and strengthening effects.
本研究调查了在不同深度进行精密磨削的C45钢表层的应变硬化和位错结构。目的是评估不同的磨削条件如何影响铁素体的力学响应和缺陷结构。采用纳米压痕法评估力学性能，同时X射线衍射分析提供了关于微应变、微晶尺寸和残余应力的数据。使用改进的威廉姆森-霍尔法和q参数分析法进一步研究了位错的特征和密度。结果表明，磨削至2μm深度的样品显示出统计存储位错的最高密度，以及最低的位错迁移率。这种情况还对应于最高的残余应力和最大比例的螺旋位错，表明强烈的应变局部化。相比之下，更深的磨削深度导致位错密度降低，并降低了应变能。观察到的趋势突出了在最浅磨削区域形成富含位错的纳米结构层。这些发现为铁素体钢的表面硬化机制提供了新的见解，并证明了磨削过程中材料去除深度如何控制亚表面微观结构和强化效果。
