JOINING METHOD OF ZIRCONIUM-BASE ALLOY AND HAFNIUM

摘要

PURPOSE:To join hafnium and a zirconium-base alloy to a satisfactory composite material by combining the zirconium-base alloy to the surface of the hanium by press welding or thermal spraying and joining diffusively both metals in the temp. region where the beta phase of the zirconium-base alloy exists then cooling quickly the joined material. CONSTITUTION:A zirconium-base alloy plate is combined to the surface of a hafnium rod by presswelding or thermal spraying to form the film of said alloy thereon in the stage for coating the zirconium-base alloy on the surface of the hafnium rod for a nuclear reactor control rod to suppress deterioration of the hafnium and to prevent liberation of oxide. The coated rod is subjected to diffusion bonding at about >=880 deg.C at which the zirconium-base alloy forms body centered cubic lattice and thereafter the rod is cooled quickly so that the beta phase remains down to an ordinary temp. on account of supercooling. The difference in volumetric expansion is decreased and the strain of the diffused surface is decreased, by which satisfactory joining is accomplished.