METASTABLE PHASE-DIAGRAMS AND RAPID SOLIDIFICATION PROCESSING

Efficient metallurgical and processing development requires ability to predict the solidification microstructure of products. Models were de veloped to calculate possible growth morphologies and phases in order to select the most efficient one for a given solidification condition. It is then possible to predict solidification microstructure selectio n maps (SMSM) indicating the microstructure as a function of the compo sition and the growth rate. A summary of the methodology of solidifica tion microstructure prediction is given. Results obtained in a large v elocity range for Al-Fe and Al-Cu systems are reviewed with experiment al comparison and emphasis on the role played by metastable phase equi libria in the modelling. Finally, an outline of the actual work extend ing this approach to multicomponent alloys is given. Provisional calcu lated solidification microstructure maps for the Al-Cu-Si system are p resented.