Lubricant-free tribology concepts for cold extrusion by interaction-reduced coatings and structures

通过减少相互作用的涂层和结构进行冷挤压的无润滑摩擦学概念

• 批准号: 244932637
• 负责人: Professor Dr.-Ing. Gerhard Hirt
• 金额: --
• 依托单位: Lehrstuhl für Lasertechnik (LLT)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/244932637?language=en
• 关键词: Lubricant; free; tribology; concepts; cold

In cold extrusion processes, lubricants are used to decrease friction and wear. Within the SPP 1676 the research consortium was able to advance the fundamental research knowledge in the field of dry extrusion of aluminum. Machines and devices were developed to realize different surface modifications and to test them in process-oriented tribological tests. The combination of laser structuring by remelting and subsequent functionalization with self-assembled monolayers (SAM) showed a significant reduction of adhered aluminum and transferred friction forces under dry conditions. Within the third project phase the efficacy of surface modifications fashioned by laser structuring by remelting as well as by functionalization will be further advanced and their application in extrusion processes will be enabled by designing die geometries in consideration of the tolerable tool loads.The approach of modifying the surface topography with laser radiation will be supplemented by the control of the chemical composition of the remelted surface layer by controlling the composition of the process gas atmosphere. Based on these surface modifications the influence on wear as well as on the achievable area-coverage of the functionalization is researched.The functionalization will be supported by adhesion layers in order to increase area-coverage, while plasma treatments after SAM-deposition will be investigated to enable cross-linking of SAM-molecules. This will improve the mechanical stability of methyl-terminated SAM on die surfaces and prevent the direct interaction between the oxidized tool-steel surface and aluminum, which leads to aluminum-adhesion usually observed in lubricant-free aluminum forming.The developed surface modifications will be evaluated by trials on a compression-torsion-tribometer and on a lab-scale cold extrusion test bench. Moreover, forming stage sequences are investigated with the aim of realizing high global strains by reducing die loads on the modified surfaces.By transferring the fundamental research knowledge gained to real die geometries and extrusion processes the consortium aims at an application-oriented conclusion of the project.

在冷挤压工艺中，润滑剂用于减少摩擦和磨损。在SPP 1676中，研究联盟能够推进铝干挤压领域的基础研究知识。机器和设备的开发，以实现不同的表面改性，并测试他们在面向过程的摩擦学测试。通过重熔和随后的功能化与自组装单层（SAM）的激光结构化的组合显示出在干燥条件下粘附的铝和转移的摩擦力的显着减少。在第三个项目阶段，通过激光结构化、重熔以及功能化进行的表面改性的效果将进一步提高，并通过考虑可承受的工具载荷来设计模具几何形状，使其在挤出工艺中的应用成为可能。激光辐射改性表面形貌的方法将通过控制重熔表面层的化学成分来补充，控制工艺气体气氛的组成。基于这些表面改性的磨损的影响，以及对可实现的面积覆盖率的功能化进行了研究。功能化将支持粘附层，以增加面积覆盖率，而SAM沉积后的等离子体处理将进行研究，使SAM分子的交联。这将提高模具表面上的甲基封端SAM的机械稳定性，并防止氧化的工具钢表面和铝之间的直接相互作用，这导致铝粘附通常观察到在无润滑剂的铝forming.The开发的表面改性将通过压缩-扭转-摩擦试验机和实验室规模的冷挤压试验台上的试验进行评估。此外，成形阶段序列进行了研究，目的是实现高的整体应变，通过减少模具负荷的修改surface.By转让的基础研究知识获得真实的模具几何形状和挤压工艺的财团旨在一个面向应用的项目的结论。