ANNEALING RELATED MICROSTRUCTURAL DEVELOPMENTS IN A TWO-PHASE ZR-2.5 NB ALLOY

摘要

Deformed/pilgered two-phase, 10-15% cubic second phase – rest being primaryhexagonal phase, Zr-2.5 Nb alloy was subjected to various annealing treatments –treatments ranging from recovery to recrystallization and grain growth. Associatedmicrostructural developments were monitored through combinations of characterizationtechniques - bulk crystallographic texture & microtexture measurements and estimationsof lattice strain and residual stress. Significant texture changes were associated only withgrain growth of the primary phase – a process facilitated by second phase coarsening.From nearly continuous presence at the primary phase grain boundaries, latter stages ofgrain growth had shown coarsened second phase present only at the tri-junctions. Thisprocess was associated with significant changes in phase-boundary nature. An effort wasmade to explain such changes from an 'extended', i.e. extended to phase boundaries, CSL(coincident site lattice) theory.