Interfacial reactions in Ta/304L and Ta/Cu/304L composites during single-shot explosive welding and post-processing annealing

Abstract

This work presents a study of recent advances in the understanding of the mechanism controlling chemical composition and the microstructure of reaction regions in a Ta/304L steel composite with and without Cu interlayers fabricated by explosive welding, both during composite formation and post-processing annealing. The microstructure of solidified melt regions (SMR) were characterized using scanning and transmission electron microscopy while phase composition by X-ray synchrotron radiation. It was found that SMR in Ta/304L plates are composed of ultra-fine-grained microstructure with a varied chemical compositions, containing elements from both combined sheets. In Ta/Cu/304L composites the melted regions located close to Ta/Cu interface composed only of a combination of Cu and Ta (small dendrites and ultra-fine grains), when the areas near the Cu/304L interface consisted of nano-grains with a more diverse chemical composition, containing elements from both sheets. No significant effect of the annealing (under the applied temperature of 700°C and for times up to 103 h) on changes in the microstructure of the SMR was observed in both plates.