Processing and microstructure of Nb-1% Zr-0.1% C alloy sheet

A systematic study was carried out to evaluate the effects of processing on the microstructure of a Nb‐1 wt. % Zr‐0.1 wt. % C alloy sheet. The samples were fabricated by cold rolling different sheet bars that were single‐, double‐ or triple‐extruded at 1900 K. Heat treatment consisted of one‐ or two‐step annealing of different samples at temperatures ranging from 1350 K to 1850 K. The assessment of the effects of processing on microstructure involved characterization of the precipitates including the type, crystal structure, chemistry and distribution within the material as well as an examination of the grain structure. A combination of various analytical and metallographic techniques were used on both the sheet samples and the residue extracted from them. The results show that the relatively coarse orthorhombic Nb2C carbides in the as‐rolled samples transformed to rather fine cubic monocarbides of Nb and Zr with varying Zr/Nb ratios upon subsequent heat treatment. The relative amount of the cubic carbide...