GOALI: Influence of Length-Scale on Diffusion During FAST (Field-Assisted Sintering Technology)

钛及其合金代表了一种重要的材料家族，具有能源效率以及机械和环境优势，但主要由于生产成本高，应用有限。电场辅助烧结技术，有时也被称为火花等离子烧结，是一种新的粉末或颗粒固化工艺，与传统方法相比，它具有成本优势。这个学术联络与工业（GOALI）项目的团队将有助于对钛和钛粉在现场辅助烧结过程中的分子扩散行为的基本理解，这将使这些材料的制造具有成本效益，同时保持材料属性，如高强度，低密度和环境惰性。这一发现将对汽车和航空航天工业产生影响。校企合作研究团队将教育大学生，并提供推广活动，以吸引高中生从事工程职业。由于扩散分析的复杂性和相互扩散系数对组分的依赖性，多组分系统中扩散数据的可用性一直很有限。这阻碍了在商业重要材料中遇到的三元或高阶系统烧结动力学的准确建模。研究小组将为钛-铝-铌体系生成三元相互扩散系数，这是汽车和航空航天应用的重要材料体系。在电场辅助烧结过程中，相平衡可以被改变，产生新的相或在加工过程中消除某些相。施加电场和微观结构长度尺度的影响将通过一系列实验和模拟进行评估，这些实验和模拟将提供对所选材料系统的相互扩散和相平衡/转变的热力学和动力学的见解。有了这一见解，钛合金可以以比现在更低的成本设计和制造具有所需性能的材料。

Titanium and its alloys represent an important family of materials providing energy efficiency along with mechanical and environmental advantages but have seen only limited application primarily due to the high cost of production. Electric field-assisted sintering technology, sometimes called spark plasma sintering, is a novel process for the consolidation of powders or particulates that offers cost advantages over conventional approaches. The team of this Grant Opportunity for Academic Liaison with Industry (GOALI) project will contribute to the fundamental understanding of molecular diffusion behavior during field-assisted sintering for titanium and titanium powders that will enable cost-effective manufacturing of these materials while maintaining material attributes such as high strength, low density and environmental inertness. The findings will impact both the automotive and aerospace industries. The collaborative university-industry research team will educate university students as well as provide outreach activities to attract high school students to engineering careers.Availability of diffusion data in multicomponent systems has been scarce due to the complexity of diffusion analyses and the dependence of interdiffusion coefficients on composition. This has prevented accurate modeling of the kinetics of sintering for ternary or higher order systems encountered in commercially important materials. The research team will generate ternary interdiffusion coefficients for titanium-aluminum-niobium systems, an important material system for automotive and aerospace applications. In the presence of an electric field during field-assisted sintering, the phase equilibrium can be altered giving rise to new phases or eliminating certain phases during processing. The effects of an imposed electric field and microstructural length scale will be assessed through a set of experiments and simulations that will provide insight into the thermodynamics and kinetics of the interdiffusion and phase equilibria/transformation for the chosen material system. With this insight, titanium alloys can be designed and manufactured with desired properties at lower cost than is available today.