Research Equipment (REG): A High Power Laser and Microscopic Image Analysis System

利用高功率激光和显微图像分析系统对多层陶瓷热障涂层进行控制实验。这些涂料是为高温应用而开发的，如陆地和航空航天车辆中使用的柴油发动机、喷气发动机和燃气轮机。目前的研究是通过将涂层试样置于低热流下进行的，已经确定了一些失效模式。为了获得更大的温度和温度梯度，现在有必要将类似的样品以及具有薄多层涂层的样品置于较大的热通量下。利用显微图像分析系统对高热流应用过程中发生的开裂过程进行交互式量化。这项研究将提供的基本理解将用于开发和设计具有更长的高温寿命的多层涂层。第二个项目是一项多学科研究，旨在开发一种热增强加工技术，以提高陶瓷加工的生产率和表面质量。该方法是利用高功率激光束在刀具刃口前方局部加热工件表面，使材料软化，增加延展性。预计这种混合技术可用于加工难切削材料。从而降低制造陶瓷零件的成本，提高尺寸和表面质量。本研究通过搭建实验平台进行实验研究，建立热传递和表面变形以及裂纹扩展模型，并实施基于过程模型的控制方案。与过程控制相关的过程传感技术也将得到发展。

A high power laser and microscopic image analysis system will be used to perform controlled experiments on multilayered ceramic thermal barrier coatings. These coatings are developed for high- temperature applications such as diesel engines, jet engines and gas turbines used in land and aerospace vehicles. Current research performed by subjecting coated specimens to low heat fluxes has resulted in identifying some of the failure modes. It is now necessary to subject similar specimens, as well as specimen with thin multi-layer coatings to large heat fluxes in order to obtain larger temperatures and temperature gradients. The cracking process occurring during the application of the high heat flux will be quantified interactively using the microscopic image analysis system. The fundamental understanding that this research will provide will be used to develop and design multilayer coatings with a significantly longer life under high temperature. The second program is a multidisciplinary investigation to develop a thermally enhanced processing technique in order to improve the productivity and surface quality in the machining of ceramics. The approach is to locally heat the surface of the workpiece by using a high power laser beam in front of the cutting tool edge so as to soften the material and increase the ductility. It is anticipated that this hybrid technique can allow for machining of the difficult-to-cut materials. Thereby reducing the cost to fabricate ceramic parts and improving dimensional and surface quality. The research seeks to perform experimental investigation by constructing a testbed, to develop models for heat transfer and surface deformation along with crack propagation, and to implement a control scheme based on the process models. In- process sensing techniques pertinent to process control will be developed as well.