Elementary processes which govern the formation of nano grained and ultra fine grained (N&UFG) zones during oscillating sliding high temperature wear (HTW)

控制纳米晶粒和超细晶粒（N

• 批准号: 268254585
• 负责人: Professor Dr.-Ing. Gunther Eggeler
• 金额: --
• 依托单位: Lehrstuhl Werkstoffwissenschaft
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/268254585?language=en
• 关键词: Elementary; processes; govern; formation; nano

HTW limits the exploitable service life of many technologically important metallic systems, like for example valve/valve seat tribo systems in Diesel engines. When a metallic tribo system is exposed to HTW, tribo layers form in the surface regions of the wear partners. These layers are of central importance for the microstructural understanding of wear resistance. The present projects aims at studying a specific deeper zone of the tribo layer, where a nano crystalline and ultrafine grained structure (N&UFG) develops during HTW. The elementary microstructural processes which lead to the formation of this N&UFG zone need to be understood to appreciate the mechanisms which govern HTW at temperatures above half of the melting point in K. After HTW exposure (of different degrees), specimens from the surface regions will be taken using focused ion beam extraction (FIB). Then the N&UFG regions will be analyzed using scanning transmission electron microscopy (STEM) in combination with a high angular annual dark field (HAADF) detector, a TEM method which is well suited to investigated collective phenomena depending on dislocations and planar defects in sufficiently large microstructural regions. The investigations will be performed using two classical model Al alloys, Al11Zn and Al5Mg, which have been reported to differ in their tendencies to form dislocation induced substructures during creep and during severe plastic deformation. They will be exposed to wear loading as disk materials in the temperature range between 300 and 500°C (under Ar atmosphere and air). A wear resistant pin made out of tool steel (German grade: 100Cr6) will be used as counter body. The scientific objective of the proposed project is to contribute to a better understanding of the elementary processes which govern the formation and evolution of the N&UFG zones of tribolayers which form in metallic materials under conditions of HTW.

htw限制了许多技术上重要的金属系统的可探索服务寿命，例如柴油发动机中的阀/阀座座椅系统。当金属底环系统暴露于htw时，磨损伙伴表面区域中形成了底环层。这些层对于对耐磨性的微观结构理解至关重要。目前的项目旨在研究底层层的特定较深区域，htw期间，纳米晶体和超细颗粒结构（N＆UFG）发展。需要理解导致该N＆UFG区域形成的基本微观结构过程，以理解在K中熔点的一半以上的温度下控制HTW的机制。（不同程度的htw暴露于不同程度），使用聚焦离子束提取（FIB）将采取表面区域的标本（fib）。然后，将使用扫描传输电子显微镜（STEM）与高角度年度黑暗场（HAADF）检测器结合使用N＆UFG区域，这是一种TEM方法，非常适合根据足够大的大型微观结构区域中的错位和平面缺陷研究集体现象。投资将使用两种经典模型AL合金AL11ZN和AL5MG进行，据报道它们在蠕变期间和严重的塑性变形过程中形成脱位诱导的子结构的趋势有所不同。它们将暴露于在300至500°C（在AR大气和空气下）的温度范围内的磁盘材料磨损。用工具钢制成的耐磨销（德国级：100CR6）将用作柜台车身。拟议项目的科学目标是有助于更好地理解控制在htw条件下以金属材料形成的Tribolayers N＆UFG区域的形成和演变的基本过程。