Deformation heterogeneity in laser-welded Eurofer

The suitability of a post-weld heat treatment is often measured in terms of reducing residual stress and/or ensuring hardness homogeneity. Here we use digital image correlation to quantify the localised deformation behaviour of laser-welded Eurofer-97 both with and without a normalising and tempering heat treatment. This is coupled with detailed microscopic analysis to investigate the mechanisms for the localised plasticity measured. We show that although the heat treatment ensures hardness homogeneity, there remains variation in grain size, texture, carbide morphology/density and tensile behaviour across the weld. Accordingly, deformation is heterogeneous under tension, even in the 'uniform elongation' regime. To capture this behaviour, a quantification of strain heterogeneity throughout the test provides a new measure of performance that indicates the suitability of both microstructure and macroscopic performance for engineering applications.