Examination of the diffusion path in a niobium-steel explosion weld interface during heat treatment

The microstructure of the interface of the explosively welded niobium-steel composite which had been subjected to heat treatments between 973–1273 K was investigated by using optical microscopy and electron probe micro-analysis. The diffusion paths at 1023 and 1273 K were constructed and interpreted by means of the FeNbC equilibrium phase diagram assuming that local equilibrium is established at all the phase boundaries.