Influence of Re-HIPing on the structure–property relationships of cobalt-based alloys

HIP-consolidation (Hot Isostatic Pressing or HIPing) of cobalt-based Stellite alloys offers significant technological advantages for components operating in aggressive wear environments. The aim of this investigation was to ascertain the effect of re-HIPing on the HIPed alloy properties for Stellite 4, 6 and 20 alloys. Structure–property relationships are discussed on the basis of microstructural and tribo-mechanical evaluations. Re-HIPing results in coarsening of carbides and solid solution strengthening of the matrix. The average indentation modulus improved, as did the average hardness at micro- and nano-scales. Re-HIPing showed improvement in wear properties the extent of which was dependent on alloy composition.

► Re-HIPing of Stellite alloys result in solid solution strengthening of matrix. ► Re-HIPing also results in precipitate coarsening of carbides. ► Abrasive wear improves after re-HIPing of Stellite 4 (8.4%) and 6 (7.3%) alloys. ► Sliding wear improves after re-HIPing of Stellite 20 (32%) alloy. ► Hardness increases at micro- and nano-scales after re-HIPing.