Fundamental Studies on Field Activated Sintering for Advanced Materials Manufacture

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The goal of this research is to address the scientific and engineering fundamentals for a new generation of field activated sintering technique (FAST) for multi-scale powders and exploit the benefits of electrical field to develop a commercially viable manufacturing process. Previous research has demonstrated that the FAST process is able to consolidate difficult to sinter powders and achieve full densification with minimal grain growth on a limited scale. This method can reduce the number of processing steps, eliminate the need for sintering aids, and can be scaled up. However, there is a lack of basic understanding, and thus the control of field effects. Therefore, the proposed work is aimed at advancing the scientific base of the new technology by modeling field effects in sintering coupled with a thorough understanding of processing-microstructure-property relationship. The specific research will comprise: (1) development of constitutive models to quantify the conduction of electrical current through sintering compacts; (2) extension of classical models for neck growth and density evolution to account for the coupling between electrical field, temperature and pressure; (3) optimization of field processing conditions to provide particular manufacturing benefits - reduced number of manufacturing steps, flexibility in powder handling, scale up capability, and (4) application of FAST for processing advanced materials (e. g., nanocrystalline). It is anticipated that the results of this research program will not only enhance the scientific foundation of field assisted sintering phenomena but also provide quantitative insights into the relevant mechanisms for developing cost effective, large scale FAST manufacturing processes for the U.S. industry. Educational opportunities for graduate and undergraduate students include coursework and lab modules for netshape processing of sintered product with this new technology at the two institutions involved.