Field-activated sintering of metallic materials - experimental study and simulation of mechanisms of matter transport

金属材料的场激活烧结——物质输运机制的实验研究与模拟

基本信息

批准号：
262396337
负责人：
Professor Dr.-Ing. Bernd Kieback
金额：
--
依托单位：
Professur für Mechanik multifunktionaler Strukturen
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/262396337?language=en
关键词：
Field activated sintering metallic materials

项目摘要

The proposed research project aims at the accurate elucidation and description of the sintering processes occurring during field activated sintering (FAST) of metallic powders. Within this project, the influence of temperature, pressure, temperature gradient, electric field and electric current density on the material-transport processes will be investigated. In order to do this, a multitude of coordinated theoretical/numerical and experimental investigations is conducted. The proposed project serves to review common hypotheses given in literature concerning e.g. thermodiffusion and electromigration in a critical manner.On the basis of the considerable progress made during the first project phase, the second project phase aims at developing and thoroughly describing the FAST process. This description will be capable of capturing the transport mechanisms during the FAST process for relevant material and powder properties in dependence of the present ambient conditions. As a result of this, the material transport during the sintering needs to be addressed explicitly, and will be included in the electro-thermo-mechanical model. The major work package of the experimental part of the project consists of sintering experiments employing systematic variations of the process parameters which are adapted regarding the investigated metallic materials. The development of the numerical model will be done at the Institute of Solid Mechanics (IFKM) and the experiments will be conducted at the Institute of Materials Science (IfWW) at TU Dresden. A major goal is the development and implementation of a finite-element model capable of modeling the growth of the particle contact and the densification during the FAST process. This has to be done under consideration of curved surfaces and external pressure as well as gradients of temperature and of electric potential, which are the driving forces of the material transport processes. By comparing the results of the numerical simulation with the specifically designed experiments the finite-element simulation is verified and subsequently the prediction of the relevant transport mechanisms and hence the optimization of the FAST process parameters is enabled. In particular a sound knowledge of field assisted sintering for arbitrary electrically conducting materials is gained.On the basis of the expected results of the project, for the first time a comprehensive description of the densification process occurring during FAST of metallic powder systems - which includes the influence of the material, particle size, surface quality, pressure, temperature and electric regimes - will be given. Transferring the assumptions made for the model systems on to real powder systems enables a more reliable design of the densification and the evolution of the microstructure. Furthermore, the scientifically sound description of the FAST process shall replace guesses not supported neither by numerical nor experimental evidence.

拟议的研究项目旨在准确阐明和描述金属粉末场活化烧结（FAST）过程中发生的烧结过程。在该项目中，将研究温度、压力、温度梯度、电场和电流密度对材料传输过程的影响。为了做到这一点，需要进行大量协调的理论/数值和实验研究。拟议的项目旨在审查文献中给出的常见假设，例如：以关键的方式进行热扩散和电迁移。在第一项目阶段取得的巨大进展的基础上，第二项目阶段旨在开发和彻底描述FAST过程。该描述将能够捕获 FAST 过程中相关材料和粉末特性依赖于当前环境条件的传输机制。因此，需要明确解决烧结过程中的材料传输问题，并将其包含在电热机械模型中。该项目实验部分的主要工作包包括采用系统变化的工艺参数进行烧结实验，这些参数根据所研究的金属材料进行了调整。数值模型的开发将在固体力学研究所（IFKM）完成，实验将在德累斯顿工业大学材料科学研究所（IfWW）进行。主要目标是开发和实施有限元模型，能够模拟 FAST 过程中颗粒接触的生长和致密化。这必须在考虑曲面和外部压力以及温度和电势梯度的情况下完成，这些是材料传输过程的驱动力。通过将数值模拟的结果与专门设计的实验进行比较，验证了有限元模拟，随后预测了相关的传输机制，从而实现了 FAST 工艺参数的优化。特别是获得了对任意导电材料的现场辅助烧结的丰富知识。根据该项目的预期结果，首次全面描述了金属粉末系统 FAST 期间发生的致密化过程 - 其中包括将给出材料、颗粒尺寸、表面质量、压力、温度和电力制度的影响。将模型系统的假设转移到真实粉末系统上，可以更可靠地设计致密化和微观结构的演化。此外，对 FAST 过程的科学合理的描述将取代既没有数字证据也没有实验证据支持的猜测。