White Etching Areas in Bearing Steel 100Cr6

申请项目的总体目标是提供关于理解WEA（白色蚀刻区）的形成机制和导致WEC（白色蚀刻裂纹）的损伤机制的开放性问题的答案。基于“微观结构变化导致裂纹形成”的研究假设，提出了本应用项目的以下部分目标：在滚动接触疲劳试验机上可重复地创建WEA/WEC。2. 高分辨率显微结构- WEA区域显微结构转变的分析表征。3. 透射电子显微镜下WEA区域的详细研究。4. WEA形成时局部温度的理论测定。5. 在连续介质力学的帮助下，在细观尺度条件下进行数值模拟，从而可以解释WEA区域观察到的微观结构变化。通过耦合数值模拟，考虑了由贝氏体组织向过饱和铁素体组织的相变，以及由于其高强度而形成的应力集中。研究的目的是证明WEA中的应力可能会非常高，从而导致该区域的裂缝形成。在拟议的项目中，不会对裂纹的形成和扩展进行明确的模拟。

The overall goal of the applied project is to provide answers to open questions regarding the understanding of the formation mechanisms of WEA (White etching areas) and damage mechanisms leading to WEC (White etching cracks). Based on the research hypothesis 'Microstructural changes lead to crack formation' the following partial goals for the applied project emerge: 1. Reproducible creation of WEA/WEC on a rolling contact fatigue testing machine. 2. High resolution microstructure-analytical characterisation of the microstructural transformations in the region of the WEA. 3. Detailed investigations of the WEA regions with transmission electron microscopy. 4. Theoretical determination of the local temperature at the formation of the WEA. 5. With the help of a continuum mechanical, numerical simulation in mesoscopic scale conditions are to be identified, with which the observed microstructural changes in the region of the WEA can be explained. Using coupled numerical simulations, the phase transformation from the bainite structure to the supersaturated ferrite is to be considered as well as the stress concentration within the WEA formed due to their high strength. The study aims to prove that the stress in the WEA could rise very high, leading to crack formation in this area. An explicit simulation of the crack formation and -propagation will not be conducted in the proposed project.