A Brief introduction of the Speaker
Prof Sir Harry Bhadeshia works on the theory of solid-state phase transformations with emphasis on the prediction and verification of structural development in complex metallic alloys, particularly multicomponent steels. Theory for the interaction of hydrogen with iron and its compounds. Subjects covered: physical and chemical metallurgy, steels, phase transformations, mathematical modelling, design of alloys, materials algorithms. Development of freely available teaching resources in metallurgy. He has supervised 97 PhD students and 39 PDRAs at University of Cambridge and QMUL. He has published ~700 papers and ~9 patents. His H-index is 116, with citation of 63950.
Abstract
Free energy of a solution is a thermodynamic function of state. It usually is assumed to be a particular value for a given phase where all the variables such as temperature, pressure, chemical composition etc. are fixed. This is convenient for systems at equilibrium.
Suppose now that the solution is not chemically homogeneous, rather there exist gradients of composition within a single phase. The free energy now becomes a function of the gradients. This has deep consequences if the gradients are steep. I will give example where this really matters in modelling solid-state phase transitions in steels in particular, but the theory is of generic value.
