Microstructural and Textural Evolution in Heat Treated Zr-2.5% Nb Pressure Tube Material Subjected to Dilatometric Studies

摘要

?-transits boundary for the Zr-2.5%Nb alloy containing 1137 ppmw of O and 650 ppmw of Fe was established using quenching dilatometry technique. The solid cylindrical samples of the alloy were ? homogenised at 1063°C and then quenched at different rates between 0.06 and 200°C/s using the quenching dilatometer. The cooling part of the dilatograms were analysed to establish continuous cooling ? transus boundary. Based on this ? transus boundary heat treatment experiments were carried out on the alloy samples by holding at temperatures 883, 870, 863, 840°C in the á + ?_(Zr) phase field and then quenching at different rates between 0.5 and 100°C/s to study the microstructural evolution and textural changes using electron microscopy techniques. An attempt has been made to correlate the transformation characteristics with the dilatograms recorded and the microstructural and textural changes have been ascertained.