Enhancement of damage tolerance of 52100 bearing steel by influencing the static and dynamic cold working features due to defined stabilized retained austenite

计划中的研究项目的目的是开发一种损伤容限52100轴承钢(德国钢级100Cr6)。从方法的角度来看，必须显著提高局部加工硬化能力，并结合高的局部应力阻力和良好的尺寸稳定性。实现这一目标的科学假设是合金和热处理的具体组合，以调整残余奥氏体量、分布和稳定性。因此，必须了解技术材料中的物理关系，并必须获得关于基本微观结构机制的深入知识。为此，必须研究在循环应力和循环诱导下残余奥氏体向马氏体局部转变的稳定化机制及其对工作温度的依赖关系。如果达到研究项目的目标，与传统轴承钢相比，确定的材料变体具有更高的损伤容忍度。局部相变提高了加工硬化率，强化了裂纹尖端周围的基体，从而避免、抑制和阻止断裂。同时提高了材料对内部缺陷的容忍度，避免了材料纯度的成本密集型增加。

The aim of the planned research project is to develop a damage tolerant 52100 bearing steel (german steel grade 100Cr6). From a methodical point of view, a significant increase in local work hardening ability combined with high local stress resistance and good dimensional stability have to be implemented. The scientific hypothesis to reach this goal is a specific combination of alloy and heat treatment to adjust the retained austenite content, distribution and stability. Therefore the physical relationships in a technical material have to be understood and a depth knowledge on the underlying microstructural mechanisms has to be acquired. For this purpose the stabilizing mechanisms acting under cyclic stress and cyclic induced local transformation of retained austenite to martensite and their dependency on increased operating temperature have to be investigated. If the aim of the research project is reached, the identified materials variant has an enhanced damage tolerance compared to conventional bearing steels. The enhanced work hardening rate due to local phase transformation strengthens the matrix around e.g. crack tips and therewith avoids, inhibits and stops fracture. Simultaneously the tolerance of the material against internal defects increases, so that the cost intensive increase of material purity can be avoided.