3D Assessment of Surface Integrity and Performance

在许多情况下，失效机制从表面开始并传播，包括腐蚀、疲劳和磨损下的失效。关键是表面光洁度(SF)和表面完整性(SI)。虽然表面光洁度得到了很大的关注，但表面完整性这一用来描述不同于整体的局部亚表面区域(残余应力、塑性变形、化学变化、硬度等)的术语却很少受到关注。传统上，人们使用简单的横截面来检查表面微结构。在这个项目中，我们将应用一套最先进的方法来尽可能全面地描述一系列尺度上的3D局部微结构。其中包括使用聚焦离子束(FIB)的连续切片、机械切片和X射线断层扫描。在后一种方法中，X射线被用来获得3D图像，而不需要对样品进行机械切片。对前一种方法至关重要的是快速有效地去除材料而不会造成损害的方法。新出现的去除破损层的方法将被开发出来，这样我们就可以获得EBSD、纹理、化学图谱、残余应力和对近地表塑性变形的洞察。这将导致世界上最好的表面完整性评估设施之一，以支持行业。此外，我们将开发微观机械方法来评估机械性能和腐蚀和磨损性能。通过这种方式，我们将把表面完整性与表面耐久性联系起来。如果我们要预测和设计表面性能，这是至关重要的。除了开发这些计量工具外，我们还将把它们应用于一系列工业案例研究，包括能源领域不锈钢的腐蚀、涡轮发动机领域热障涂层的性能、WC-Co涂层和纳米结构涂层的磨损性能。我们的工业指导小组将确定进一步的案例研究。

In many cases failure mechanisms initiate and propagate from the surface, including failure under corrosion, fatigue and wear. Critical to this is the surface finish (SF) and the surface integrity (SI). While surface finish has received much attention, surface integrity, a term used to describe the localised sub-surface region that differs from the bulk (residual stresses, plastic deformation, chemical changes, hardness, etc) has received much less attention. Traditionally people have used simple cross sections to examine the surface microstructure.In this project we will apply a suite of state-of-the-art methods to characterise as fully as possible the local microstructure in 3D across a range of scales. These include serial sectioning using a focused ion beam (FIB), mechanical sectioning and X-ray tomography. In the latter X-rays are used to obtain a 3D picture without mechanically sectioning the sample. Critical to the former methods are the means of removing material quickly and efficiently without introducing damage. Emerging methods to remove the damaged layer will be developed such that we can obtain EBSD, texture, chemical mapping, residual stress and insights into plastic deformation near-surface. This will lead to one of the best surface integrity assessment facilities in the world to support industry. In addition we will develop micromechanical methods to assess mechanical properties and corrosion and wear performance. In this way we will relate surface integrity to surface durability. This is critical if we are to predict and engineer surface performance. In addition to developing these metrology tools we will apply them to a set of industrial case studies including corrosion of stainless steel for the energy sector, the performance of thermal barrier coatings for the turbine engine sector, the wear performances of WC-Co coatings and nanostructured coatings. Further case studies will be identified by our industrial steering group.