Indentation damage characterisation in advanced materials

材料的硬度是可以评估的最基本的机械性能之一。硬度显著影响与磨损相关的性能，因此在开发用于此类应用的材料时是一个极其重要的参数。表面处理（例如，喷丸硬化，由此用硬的“喷丸”珠冲击加工的材料）也可以导致硬度的分级，因此深度分布可以提供关于该工艺的功效的极其有用的信息。考虑到这一点，目前NSERC RTI的应用是一个自动化的，最先进的压痕系统，作为一个迫切需要的替代品，约40岁的维氏硬度计，不再可用，和一个类似的年龄显微维氏硬度计，现在也被证明是不可靠的。迫切需要更换，以支持达尔豪西工程和科学学院正在进行和最近获得的几个主要研究方案。我们将使用所需的系统评估各种先进材料，包括粉末冶金（PM）和增材制造（AM）处理的轻金属和铁合金、高耐磨性金属陶瓷和涂层、导电聚合物复合材料等。我们还将评估一种新型超声脉冲水射流（UPWJ）方法对PM和AM处理的合金表面进行“喷丸”的效果;这种由加拿大中小企业发明的“绿色”技术，提供了彻底改变表面喷丸的潜力。自动化测试系统将允许硬度深度分析、压痕尺寸效应的评估（即硬度对施加载荷的依赖性）、多相材料的硬度绘图以及划痕测试。此外，将金刚石压头尖端转换为平面金刚石冲头，将允许微柱压缩测试;这里可以使用聚焦离子束（FIB）显微镜在表面上铣削小的方形或圆柱形支柱，然后使用压痕单元进行压缩测试。所要求的多功能压痕系统还允许广泛的压痕载荷，覆盖大约五个数量级，最大40 kg，与我们以前的（不再起作用的）Vickers系统相比，显著提高了可用性。如上所述，硬度是材料最基本的性能之一，因此所要求的设备的适用性非常广泛。预计它将支持教师的工作，他们共同监督30多名HQP。

The hardness of a material is one of the most fundamental mechanical properties that can be evaluated. Hardness significantly impacts properties relating to wear, and is therefore an extremely important parameter when developing materials for such applications. Surface treatments (e.g., shot peening, whereby the processed material is impacted with hard 'shot' beads) can also result in gradation of hardness, so depth profiles can provide extremely useful information about the efficacy of the process. With that in mind, the present NSERC RTI application is for an automated, state-of-the-art indentation system as an urgently needed replacement for an approximately 40-year old Vickers hardness tester that is no longer serviceable, and a similar age micro-Vickers that is also now proving unreliable. A replacement is urgently required in support of several major ongoing and recently awarded research programmes in the Faculties of Engineering and Science at Dalhousie.******We will be evaluating a broad variety of advanced materials with the requested system, including powder metallurgy (PM) and additive manufacturing (AM) processed light metals and ferrous alloys, high wear resistance cermets and coatings, conducting polymer composites, etc. We will also be assessing the effects of a novel ultrasonic pulsed water jet (UPWJ) method for ‘peening' PM and AM processed alloy surfaces; this 'green' technology, invented by a Canadian SME, offers the potential to revolutionise surface peening. The automated test system will allow hardness depth profiling, evaluation of indentation size effects (i.e. the dependence of hardness upon applied load), hardness mapping for multi-phase materials, and scratch testing. In addition, conversion of the diamond indenter tip to a flat diamond punch, will allow micropillar compression testing; here small square or cylindrical pillars can be milled on a surface using a focused ion beam (FIB) microscope, and then compression tested using the indentation unit.******The requested multi-functional indentation system also allows for a broad range of indentation loads, covering roughly five orders of magnitude up to maximum of 40 kg, giving significantly increased usability over our prior (and no longer functional) Vickers system. As noted above, hardness is one of the most fundamental materials properties, and consequently the applicability of this requested equipment is extremely broad. It is expected that it will support the work of faculty who are collectively supervising more than 30 HQP.**