Towards computational materials design and upscaling of alternative binder cemented carbides
Time: Fri 2020-02-21 10.00
Subject area: Materials Science and Engineering
Doctoral student: David Linder , Materialvetenskap
Opponent: Dr. Jonas Östby, Sandvik Coromant
Supervisor: Professor Annika Borgenstam, Materialvetenskap, Metallografi; Professor John Ågren, Materialvetenskap
Increasing demands on economic, social and environmental sustainability throughout society is putting pressure on the development of new and improved materials for resource efficiency, improved component life-time and substitution of toxic or rare elements. For the cemented carbide industry, as a major provider of tools for e.g. mining and metal cutting which are integral parts of many production chains, this may require complete or partial substitution of cobalt. Cobalt ore is primarily mined in conflict regions and cobalt powder has been shown to be carcinogenic upon inhalation. Substitution of this element could therefore have significant impact on several aspects of society. However, it is far from trivial to substitute this critical element in cemented carbide production. Nearly a century of materials and product development has made state-of-the-art cemented carbides with cobalt binder phase one of the most successful engineering materials. Over the years, accumulated investments throughout the supply chain has made these materials indispensable in industrial production. When envisioning cobalt substitution, it is therefore critical to generate new methods for accelerated materials development and standardised materials qualification. This will enable faster and more reliable development of new materials with the potential to substitute cobalt throughout the industry.
The present thesis is focused on the continued development of an integrated computational materials engineering framework for materials design as well as the development of quality control methods for alternative binder cemented carbides. The existing computational framework is here extended with a model for fracture toughness which allows for property trade-off between hardness and toughness. The extended framework is shown to replicate experimentally well-established property combinations and is thereby applicable for computational design of cemented carbides for specific applications. Furthermore, conventional quality control methods based on magnetic properties are evaluated and further developed for alternative binder cemented carbides. Combining these results on computational materials design and the steps towards standardised quality control has the potential to greatly accelerate future development of cemented carbides, both for cobalt substitution and for improved component life-time.