On the role of processing parameters in sintered new Co-based (W,Al) alloys

The demand for enhanced material performance and efficiency in high-temperature applications has motivated the development of novel Co-based superalloys. Co-Al-W-based superalloys with the gamma/gamma' structure have suitable properties for use at high temperature and are good candidates for replacing Ni-based superalloys in some applications. The current generation of Co-Al-W-based alloys has superior wear, corrosion, and oxidation resistance. The poor precipitation strengthening of these alloys compared to that of Ni-based superalloys can be overcome by designing the alloying system to promote gamma'-Co-3(Al, W) precipitation. In this work, the compositions of the selected Co-Al-W-based alloys were chosen because they improve the precipitation strengthening of the alloys. Starting from powders, the materials were fabricated by mechanical alloying (MA) and subsequently consolidated by field assisted hot pressing (FAHP). The prepared Co-Al-W superalloys have a large amount of well-dispersed nanoprecipitates in their microstructures and have nearly full density. The effects of the MA and consolidation process (FAHP) conditions on the microstructures and mechanical properties of selected samples are determined by comparing the samples. (C) 2016 Elsevier B.V. All rights reserved.