Acquisition/Development of Equipment for Processing and Characterization of Functionally Graded Materials

该补助金支持圣地亚哥州立大学的烧结和烧结中功能梯度材料（FGM）的非破坏性表征设备的收购和开发。新的仪器将增加烧结连续理论领域的建模工作。这一理论正在成为宏观分析烧结工艺过程的基础，包括传统的粉末热处理和新的领域，如微波烧结。连续体方法能够预测烧结下的形状变形和密度分布，这在粉末材料的净成形加工建模中至关重要。从而成功地解决了粉末处理的一个重要问题--尺寸控制.在功能梯度材料的制备过程中，不同部位的烧结速度不同，不均匀的收缩会导致缺陷的形成和粉末试样的损坏。如果预测建模和实验没有进展，FGM的成本可能仍然太高。新的仪器将能够利用和比较评估两种主要的方法烧结功能梯度材料：常规烧结外部加热和微波烧结。虽然通过外部加热的常规烧结通常应用于已经分级的绿色试样，但在微波烧结中，由于粉末试样内的非均匀温度分布而出现孔隙率梯度。在功能梯度材料的烧结过程中，形状畸变和损伤是两个最重要的已知问题。我们还将开发一种独特的超声波检测设备。该设备将在烧结过程中结合粉末材料的硬度测量和无损超声表征。对于该系统，我们将获得共焦法布里-珀罗干涉仪。这是一种创新的实验技术，将使一个全面的综合和比较检查的传统和微波烧结动力学（包括收缩和表面积减少）和损伤检测。 建模和实验的集成为广泛的烧结操作的在线过程控制提供了基础。该项目的更广泛的影响包括功能梯度材料日益增长的工业重要性，这些材料用于连接不同的材料，用于微电子设备，生物植入物等。此外，收购和开发的设备将有助于多个圣地亚哥州立大学教职员工的研究计划。目前在粉末加工和非破坏性材料评估方面的积极研究计划将受益。新仪器还将有助于磁性材料制造和加工表征领域的研究计划。本项目的开发部分假设本科生的参与相当大，他们将能够在他们的高级设计项目的框架内探索新的实验能力。

This grant supports the acquisition and development of equipment for sintering and in-sintering non-destructive characterization of functionally graded materials (FGM) at San Diego State University. The new instrumentation will augment modeling efforts in the area of the continuum theory of sintering. This theory is becoming the basis for macroscopic analysis of technological processes of sintering including both conventional powder thermo-processing and novel areas such as microwave sintering. The continuum approach enables the prediction of shape distortions and density distributions under sintering which are critical in modeling net-shape processing of powder materials. Thereby one of the most important problems of powder treatment - dimension control can be successfully resolved. In processing of FGM, sintering rates differ with position and uneven shrinkage may lead to defect formation and damage of a powder specimen. Without advances in the predictive modeling and experimentation, the cost of FGM may remain too high. The new instrumentation will enable the utilization and comparative assessment of two main approaches for the sintering of FGM: conventional sintering by external heating and microwave sintering. While conventional sintering by external heating is usually applied to already graded green specimens, in microwave sintering, porosity gradients appear due to a non-uniform temperature distribution within powder specimens. In sintering of FGM, shape distortions and damage are two most significant known problems. We will also develop a unique dilatometric-ultrasonic testing device. This device will incorporate both dilatometry and nondestructive ultrasonic characterization of powder materials during the sintering process. For this system, we will acquire a Confocal Fabry-Perot Interferometer. This is an innovative experimental technique that will enable a comprehensive integrated and comparative examination of both conventional and microwave sintering kinetics (including shrinkage and surface area reduction) and damage detection. Integration of modeling and experiments should provide the basis for on-line process control for a wide range of sintering operations. %%%Broader impacts of the project include the growing industrial importance of the functionally graded materials, which are used in joining of dissimilar materials, in micro-electronic devices, bioimplants, etc. Furthermore, the acquired and developed equipment will contribute to the research programs of multiple San Diego State University faculty members. Currently active research programs in powder processing and non-destructive materials evaluation will benefit. The new instrumentation will also contribute to the research program in the area of fabrication and in-processing characterization of magnetic materials. The development part of this project assumes considerable involvement of undergraduate students who will be able to explore new experimental capabilities in the framework of their senior design projects.