Repaired article and material and method for making

Abstract

A composite weld wire, for use in repairing an article of a Co base alloy, comprises the sintered product of a mixture, by weight, of about 50-90% of the Co base alloy and about 10-50% of a Ni base alloy consisting essentially of, by weight, about: 1.5-2.5% B, 2-5% Al, 2-4% Ta, 14-17% Cr, 8-12% Co, with the balance Ni and incidental impurities. Conveniently, the alloys initially are in powder form. A repaired Co base alloy article including a surface discontinuity, such as a crack or void, comprises a welded repair at the discontinuity using the weld wire. In another form, the article includes a first diffusion bonded repair alloy at the discontinuity and a second repair alloy welded over the first repair alloy using the composite weld wire. One form of a method for repairing the article includes first removing oxides from the discontinuity, diffusion bonding the first repair alloy at the discontinuity, and then welding the second repair alloy over the first repair alloy using the composite weld wire. In another form of the method, the repair alloy is welded directly over the discontinuity, particularly in the vicinity of a hole through a surface of the article. The total mount of B in the weld wire, or weld repair alloy, is in the range of about 0.2-1.2 weight % to provide desired weld flow without resulting in reduction in ductility and mechanical properties.