Abstract: Microstructure of a new zirconium alloy sheet strip with good punching properties was studied by means of scanning electron microscopy and ultra high resolution transmission electron microscopy, including grain and second phase particles, and to explore the effect of annealing temperatures on the microstructure of strip under vacuum heat treatment. The results show that the average grain size of the finished strip of the new zirconium alloy sheet is 2.17 μm. There are two textures of {0001}<1010> and {0001}<1120>. Most of the grains {0001}<1120> parallel strip RD direction, less grain with <1010> parallel strip RD direction. The second phase particles are distributed inside the grain and at the grain boundary, with an average size of 114 nm, a large size is an irregular elliptical Zr-Nb-Fe phase, and a smaller is a circular β-Nb phase. As the heat treatment annealing temperature decreases, the strip grain size decreases, and the second phase particles are fine and dispersed. The good punching performance of the new zirconium alloy sheet is mainly due to the fact that the rolling accumulating strain-induced recrystallization process is sufficient, resulting in fine grain and broken twins. Relative to rolling deformation, annealing has no significant effect on strip punching performance.

Key words: new zirconium alloy, microstructure, second phase particle, annealing, precipitated phase, texture