Process modelling to improve materials properties and microstructure for aerospace applications

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The proposed research program is based on the relationship in materials science between the operating parameters for the elaboration and manufacturing processes of advanced materials and their resulting microstructure and mechanical/physical properties. To optimize the properties of materials for specific applications, it is always necessary to have a good knowledge of the evolution of material microstructure (grain size, porosity, segregation, phase distribution, work hardening, etc.) to control carefully the operating parameters of processing steps (temperature, strain rate, cooling rate, pressure, etc.). It is important to develop the physical modelling of materials transformation under different conditions to identify the main driving parameters. Then, it is possible to implement the models in finite element analysis tools to predict the resulting microstructure at different points and the desired properties of the parts. For the present proposal, we would concentrate the effort on the modelling of specific steps of advanced processes for the fabrication of high temperature components used in the aerospace industry. The main objectives of the research program are: 1) identify the process parameters that have a major influence in the resulting materials microstructure; 2) model the physical behavior of the materials under the processing conditions; 3) determine by numerical simulation the relation between materials microstructure and targeted functional properties for given applications. This research approach will be applied to: 1) determination of conditions leading to hot crack formation during electron beam welding of turbine blades made of nickel superalloys; 2) fabrication of ceramic matrix / ceramic fibers composites by a patented methodology adapted from resin transfer moulding of fiber reinforced polymer composites. All these research projects would be partly supported by industrial partners. The activities of the research program are strongly related to the highly prioritized domains for Canadian industry in advanced materials and fabrication technologies for the aerospace industry. The activities will lead to the development of approaches for the numerical modelling of the behaviour of high performance materials specifically designed to operate at high temperature such as those used in the hot section of turbine engines. The originality of the research is based on the application of numerical modelling to novel processes for the fabrication of components for production scale needs. The careful control in the materials processing is absolutely necessary for the selected specific high performance materials to obtain the desired properties.