Cooling Rate Correlation between Microstructural Phases and Part Dimensions for EBM-Fabricated Parts

该奖项支持电子束熔化工艺的基础研究，电子束熔化工艺是一种利用粉末金属制造三维形状的添加剂制造技术。逐层制造过程促进了不同的微结构特征，这些特征取决于冷却速度，这些冷却速度受零件尺寸等因素的影响。网状和泡沫蜂窝结构是添加剂制造的一个特殊好处，可用于改善或增加航空航天和其他工业中生产部件的强度与重量比。以前，使用钛合金通过电子束熔炼制造的这些网状和泡沫蜂窝结构包含钛马氏体脆性相，本研究假设，可以通过在制造过程中控制冷却速度来避免这种脆性相。冷却速度将用多波长高温计测量，以获得逐点、逐层的部件温度；并将确定在不影响机械性能和微结构架构的情况下可以制造的最小部件尺寸。研究结果和这些结果的传播将为广泛的添加剂制造和金属制造社区提供建议和战略，以避免发生脆性微结构，而无论零件尺寸如何。钛马氏体脆性相的缺乏将允许在不影响机械性能的情况下自由设计包含网状和泡沫蜂窝结构的部件，这将为使用添加剂制造技术直接制造下一代金属部件提供前所未有的好处。这项研究将在德克萨斯大学埃尔帕索分校进行，这是一所为少数族裔服务的机构，学生人口以西语裔为主，为参与该项目的学生在不断增长的添加剂制造领域提供无与伦比的体验。

This award supports fundamental research on the electron beam melting process, an additive manufacturing technology that builds three-dimensional shapes out of powder metals. The layer-by-layer fabrication process promotes distinct microstructural features dependent on cooling rates that are affected by part dimensions, among other factors. Mesh and foam cellular structures are a particular benefit of additive manufacturing and can be used to improve or increase the strength-to-weight ratio of production parts in the aerospace and other industries. Previously, these mesh and foam cellular structures fabricated by electron beam melting using a titanium alloy contained a titanium martensitic brittle phase that, hypothesized in this research, can be avoided by controlling the cooling rates during fabrication. Cooling rates will be measured with a multi-wavelength pyrometer to obtain point-specific, layer-by-layer part temperatures; and the smallest part dimensions that can be fabricated without compromising mechanical properties and microstructural architectures will be determined. Research results and dissemination of these results will provide recommendations and strategies to the broad additive manufacturing and metals fabrication communities to avoid the occurrence of brittle microstructures regardless of part dimensions. The lack of the titanium martensitic brittle phase will allow freedom in the design of parts containing mesh and foam cellular structures without compromising mechanical properties, which will provide an unprecedented benefit for using additive manufacturing technologies to directly fabricate next generation metallic components. The research will be performed at the University of Texas at El Paso, a minority serving institution with a Hispanic-majority student population, providing an unparalleled experience for the students involved in the program in the growing field of additive manufacturing.