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Integrated Modelling and Analysis of Multiple Component Carbides in Welded hardfacings

Periodic Reporting for period 1 - NuWeld (Integrated Modelling and Analysis of Multiple Component Carbides in Welded hardfacings)

Reporting period: 2018-10-01 to 2020-09-30

Welded hardfacings are functional layers applied to the surface of steel components to improve the wear and/or corrosion resistance with typical applications in civil engineering, mining, agriculture, recycling and maritime industries with a huge market. The structure of the hypereutectic Fe–Cr–C hardfacing alloy consists of a large quantity of primary carbides ‘M7C3’ (where M could be Fe, Cr, i.e. (Fe, Cr)7C3) or other solution elements replacing Cr or Fe) within an eutectic matrix (Austenite+finer carbides). A particular technical research focus of the project is on investigating factors controlling the crystal/lattice structure and properties of the carbides and on developing approaches for combined performance improvement and structure refinement through integrated physical based predictive simulation and analysis. The R&D involves development in theories, new materials, data-led research tools and systematic data which is essential for the materials design and process optimisation.

The interdisciplinary research is built on previous establishments from the team and project partners to advance the scientific understanding and development of an important material group based on advanced physical based modelling. The theories, advanced tool, new materials and data are transferable to other areas of materials and processing developments. Improvement of the structure and properties (either the primary carbides or the matrix) of the hardfacing to increase its wear resistance has a significant economic and social impact given its wide applications (e.g. efficient use of metal resources, competitiveness of industries and use of advanced technologies). Apart from the technical research and development, the project will continue to contribute to the global effort in applying data science in materials and processing innovation through data-driven and data-informed technologies.

The proposed project aims to investigate the crystal/lattice structure and properties of carbides in welded hardfacings and the mechanisms and technologies for carbide strengthening and refinement. One area is to investigate the effects of different solution elements including RE elements on the crystalline/lattice structure and properties of primary carbides using the first principle calculations; Another area is to develop materials with refined structures integrating ab initio evolutionary algorithm techniques and physical modelling. The project covers interdisciplinary work to develop new knowledge, technology development through research, training/knowledge exchange and collaboration.
Through five highly integrated work packages, the project has covered work on many aspects including development of fundamental theories and data, development of integrated experimental- physical-engineering modelling system for new materials development. One main research work focuses on integrated experimental and physical modelling of different materials systems concentrating on the effects of alloying elements and vacancy defects on the structure and properties of different carbides. Systematic work is performed on a wide range of doping elements including rare earth elements, critical to the structures and functional properties of welded hardfacings. The work also systematically studied some fundamental material issues including the effect of site occupation of doping elements on the elastic and plastic properties, the effect of vacancy (Metal and nonmetal elements), energy in element diffusion, combined effect of vacancy defects and doping elements. These are important fundamental questions with potential to bring new insight to revolutionise the composition design and processing optimisation of the advanced alloys.

Another area of work is combining materials discovery and composition optimisations which is a novel way for structure and property optimisation. One main achievement is the identification of compounds suitable to act the nucleation sites for austenite, ferrite and multicomponent carbides. Advanced program for materials discovery and interface program developed are used to streamline the data at different dimensions, linking large domain data to specific material application cases. A practical and economic procedure with different data setting within a product life cycle framework is developed linking composition design to the structure and performances of different carbides. The work also links physical modeling with engineering modelling (FE modelling), integrating in-depth understanding of the growth model of M7C3 carbides, nucleation, internal feature/defects to the behavior of the carbide under complex conditions in services.

The outcomes include fundamental theories, new materials and structure refinement mechanism, which opens up new areas in tailoring the trade-off between key properties. The work has made significant progress in research, career development for young researchers and enterprise activities. New materials with refined structure and enhanced balance between hardness and toughness is developed. Three major journal papers have been published/accepted for publications with two major papers are under review. The work was contributed to the workshop organized by the EU Materials Simulation Council and more than 5 conference presentations including two as keynote speeches. The work contributes to the international effort in developing data-informed and data-driven research in materials and processing.
The key technical development directly impacts the material design providing important data for balance the trade-off between hardness and toughness, ductility in particular through the use of rare earth elements. The identification of new effective nucleation compound has resulted in new materials with significant improvement on the structure refinement and properties. The project also involved works linking with industrial partners including supporting several SMEs in materials research and analysis. The project has accelerated the EF and other young researchers to reach a leading position. In her new post, the EF is transferring her skills in sophisticated modelling developed in the project to advanced aerospace materials with several EU companies and R&D institutions.
The work has been shared at several platforms and events organised by leading policy making organisations (e.g. the European Materials Simulation Council). The extensive dissemination activities through publications, conferences, workshops, etc, have exposed the work to different audiences in R&D, industries, as well as policy makers. The project is a representative case for applying advanced modelling and data onto traditional industries with huge economic and environmental benefits. The project has been communicated with the general public and developed extensive education and training materials associated advanced alloy design, fundamental quantum mechanics, practical use of modern software. The link between physical modelling and engineering shared will continually contribute to global effort in applying data-driven or data informed approach in new materials discovery and development as well as education in STEM and general scientific development for society.
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