Microstructural entropy and the scatter in toughness
A. A. B. Sugden and H.K.D.H. Bhadeshia
A. A. B. Sugden and H.K.D.H. Bhadeshia
There is evidenced that some of the scatter in toughness data from wrought and welded steels can be attributed to variations in microstructure (and hence mechanical properties). A simple method is developed to represent the degree of inhomogeneity in the primary microstructure of steel welds. The method involves the calculation of microstructural entropy, using an equation that includes the volume fractions of all the phases deemed relevant, the equation being similar to one commonly used in deriving configurational entropy of solid solutions. It is demonstrated, by comparison with experimental data, that the microstructural entropy can be correlated directly with the extent of scatter in toughness data. The limitations of the method are also discussed.
