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

钛及其合金是一类重要的材料，具有能效、机械和环境方面的优势，但主要由于生产成本较高，其应用有限。电场辅助烧结技术，有时被称为放电等离子烧结，是一种用于粉末或颗粒的固结的新工艺，与传统方法相比具有成本优势。这一GOALI学术联络机会项目的团队将有助于从根本上理解钛和钛粉末在现场辅助烧结过程中的分子扩散行为，从而在保持高强度、低密度和环境惰性等材料属性的同时，实现这些材料的成本效益制造。这一发现将对汽车和航空航天行业产生影响。大学-产业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互扩散系数对组成的依赖，多组分系统中扩散数据的可用性一直很少。这阻碍了对在商业上重要的材料中遇到的三元或更高阶系统的烧结动力学的准确建模。该研究小组将生成钛-铝-铌系统的三元互扩散系数，钛-铝-铌系统是汽车和航空航天应用的重要材料系统。在电场作用下，可以改变烧结过程中的相平衡，产生新的相或消除某些相。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来评估，这些实验和模拟将提供对所选材料体系的互扩散和相平衡/转变的热力学和动力学的洞察。有了这一见解，钛合金的设计和制造就能以比目前更低的成本设计和制造出所需的性能。

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.