In this study, the sub-surface structure of a railroad crossing made of Hadfield steel was characterized. The microhardness profile and metallographic examination, in addition to XRD, EBSD, and TEM analyses, were conducted on zones near the surface (damaged), where the rolling contact fatigue was operative. It was confirmed that mechanical twinning was the main deformation mechanism operative under these circumstances, through metallographic examination, Taylor analysis, misorientation profiles, TEM micrographs, and diffraction patterns. Further evidence suggested that near the affected surfaces, where superficial cracks were observed, nanotwins and small traces of ε (h.c.p) and α' (b.c.t) martensite were detected, in conjunction with dynamic recrystallization. This last phenomenon was verified due to the presence of very small grains located at the grain boundaries with random crystallographic orientation, the high local misorientation difference between the small grains and the large ones, and finally due to the appearance of the small annealing twins. These results are discussed based on the local misorientation, Schmid and Taylor analysis, twin types, and crystallographic orientation.

在这项研究中，对哈德菲尔德（Hadfield）钢制成的铁路道口的地下结构进行了表征。除XRD，EBSD和TEM分析外，还在表面附近（损坏）的区域进行了显微硬度分布和金相检查，该区域会产生滚动接触疲劳。通过金相检查，泰勒分析，取向差分布，TEM显微照片和衍射图谱，可以确定在这种情况下机械孪晶是主要的变形机制。进一步的证据表明，在受影响的表面附近观察到了表面裂纹，结合动态重结晶，发现了纳米孪晶和少量痕量的ε（hcp）和α'（bct）马氏体。后一种现象得到了验证，这是由于位于晶粒边界且晶粒取向随机的非常小的晶粒，小晶粒和大晶粒之间的局部取向差高，最后是由于出现了小退火孪晶。这些结果基于局部取向错误，Schmid和Taylor分析，孪晶类型和晶体学取向进行了讨论。