The effect of annealing on hardness, microstructure and delayed hydride cracking in Zr–2.5Nb pressure tube material

Evaluation of variables affecting crack propagation by Delayed Hydride Cracking in Zr–2.5Nb with different heat treatments

“…For this reason, several studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] have been conducted in order to elucidate the variable dependence of cracking mechanism.…”

“…It has been observed that annealing of Zr-2.5Nb pressure tube material at temperatures between 350-500°C reduces DHC velocity [3,[5][6][7]12].…”

Annealing of cold worked two-phase Zr-2.5 Nb—Associated microstructural developments

“…The impressive range of literature on the subject is, however, concentrated mostly on annealing of singlephase metallic materials -including alloys containing hard nonshearable particles. Studies on annealing in common two-phase (with shearable or semi-shearable 2nd phase) alloys are less frequent [39][40][41][42][43]; while such studies in two-phase Zr alloys are rare [44,45]. This was the motivation behind the present study.…”

Optimization of stress relief heat treatment of PHWR pressure tubes (Zr–2.5Nb alloy)

“…They are stress relieved at 400°C for 24 h. As no intermediate annealing is involved, the micro-structure of non-autoclaved tube consists of a grain surrounded by continuous b-phase having length in the range of 5500 ± 3100 nm and thickness 300 ± 140 nm. After 24 h of stress relieving, their length becomes 4500 ± 1500 nm and thickness 240 ± 65 nm [5,10]. Higher reduction in particle size and larger increase in inter-particle spacing is achieved in the hot extrusion followed by pilgering with intermediate annealing as compared to cold-drawing route.…”