DIFFUSION JOINING JOINT AND JOINING METHOD FOR NI-BASE SUPER ALLOY

摘要

PURPOSE:To obtain a joining joint having excellent high-temp. ductility and creep characteristic by specifying the contents of B and Si and average crystal grain size in the joint part of a diffusion joining joint for Ni-base super alloys. CONSTITUTION:Oxide films 2, 2' of Al2O3 or TiO2 formed on the joint surfaces of the Ni-base super alloys 1, 1' which are a base metal are removed to form clean surfaces 3, 3' on the joint surfaces. Ni-base alloy film 4, 4' which have the melting temp. lower than the m.p. of the Ni-base super alloys 1, 1' and contain =0.05wt% B and =0.1wt% Si are coated to 5-30mum thickness on the cleaned joint surfaces 3, 3'. The coatings 4, 4' are then mated with each other and are pressurized under heating at the temp. above the melting temp. of the Ni-base alloy films 4, 4' which are the coating layers and below the m.p. of the Ni-base super alloys 1, 1' in a nonoxidizing atmosphere. The Ni-base super alloys are thereby diffusively joined and the crystal grain size of the joint part 5 is increased to =1.0mm in average grain size.