Tribological Potentials of PVD-Coated Mircotextures - TriPot

近年来，无油成形模具的表面功能化研究取得了显著进展。在已完成的SFB 747“微冷成形”和最近完成的SPP 1676“成形技术中通过干法加工实现可持续生产”中，申请人的研究小组在使用微纹理和PVD硬涂层成形工具进行干法成形方面进行了深入的研究。在SFB747中，重点放在微部件(直径≤1 mm)的冷成形上，而在SPP1676中，重点放在宏部件的无润滑剂大块成形工具的开发上。对于这两种应用，都可以通过对刀具表面进行微织构和随后的PVD硬涂层来显著降低摩擦和磨损。此外，在表面粗糙度和尺寸精度方面，无润滑剂成形零件的质量也得到了显着提高。SFB 747和SPP 1676的研究侧重于实施干法成型工艺的技术解决方案。在这些项目中，由于更多的技术导向，不可能对微观结构、表面下边界层的机械性能和所产生的摩擦学上的PVD涂层之间的复杂相互作用进行更基本的描述或建模。因此，几个基本问题仍然悬而未决。例如：铣削参数对加工边界层的微观形貌和机械性能有何影响？这些性能对摩擦学有何影响？微结构和材料配对的各种参数对所产生的干滑动摩擦和磨合行为有什么影响？当达到哪个法向接触应力时，摩擦力与法向力成比例增加，而与宏观接触面无关(库仑摩擦)？微观织构和涂层的性质如何影响粘着、弹性滞后、塑性变形和磨损这四种基本摩擦机制？如何设计微观纹理和PVD涂层以满足特定的三方面要求？是否有可能使用人工神经网络来预测假想的微结构的摩擦学性能？这些问题是这里提出的研究提案的主题。

In recent years, significant progress has been made in surface functionalization of forming tools for lubricant-free forming. In the completed SFB 747 "Micro Cold Forming" and in the recently completed SPP 1676 "Sustainable Production through Dry Processing in Forming Technology", the applicants' research groups worked intensively on dry forming using micro textured and PVD hard-coated forming tools. In the SFB 747 the focus was on cold forming of micro components (diameter ≤ 1 mm), while in the SPP 1676 the focus was on the tool development for lubricant-free massive forming of macro components. For both applications, it was possible to reduce friction and wear significantly by micro-texturing and subsequent PVD hard-coating of the tool surfaces. Additionally a significant increase of the quality of lubricant-free formed workpieces in terms of surface roughness and dimensional accuracy was achieved. The research in the SFB 747 and the SPP 1676 focused on technological solutions for the implementation of dry forming processes. A more fundamental description or modeling of the complex interactions of the micro-texture, the mechanical properties of the boundary layer below the surface and the PVD coating on the resulting tribology was not possible within these projects due to their more technological orientation. Several fundamental questions thus remained open. For example: What influence do the milling parameters have on the resulting microtopography and the resulting mechanical properties of the machined boundary layer and how do these properties affect the tribology? What influence have the various parameters of the microtexture and the material pairing on the resulting dry sliding friction and the run-in behavior? Up to which normal contact stress does the frictional force increase proportionally with the normal force, regardless of the macroscopic contact surface (Coulomb friction)? How do the properties of the microtexture and the coatings influence the four basic friction mechanisms adhesion, elastic hysteresis, plastic deformation and abrasion? How to design microtextures and PVD coatings to meet given triblogical requirements? Is it possible to predict the tribological properties of hypothetical microtextures using artificial neural networks? These questions are the subject of the research proposal presented here.