Neutron Diffraction Measurement of Texture Variations Near a Weld in a Zr-2.5% Nb Plate

Abstract

A welded Zr-2.5%Nb plate with a texture similar to that of a CANDU^* nuclear reactor pressure tube has been studied to determine the texture variations in the fusion zone and the heat affected zone (HAZ). The texture of the HAZ is explained by preferential growth of (001)[110] grains in the high-temperature bcc phase, with subsequent variant selection on cooling to enhance the volume fraction of (0002) normals perpendicular to the line of the weld. The same texture is observed in the fusion zone along with a (001)[100] texture component arising from solidification. The textures of the fusion zone and HAZ are not expected to increase the susceptibility of the welded plate to delayed hydride cracking.