Microstructure and compression strength of Co-based superalloys hardened by gamma' and carbide precipitation Articles uri icon

authors

  • Carton Cordero, Marta
  • CAMPOS GOMEZ, MONICA
  • Freund, Lisa P
  • Kolb, Markus
  • Neumeier, Steffen
  • Goeken, Mathias
  • TORRALBA CASTELLO, JOSE MANUEL

publication date

  • September 2018

start page

  • 437

end page

  • 444

volume

  • 734

international standard serial number (ISSN)

  • 0921-5093

electronic international standard serial number (EISSN)

  • 1873-4936

abstract

  • A Co-based superalloy, Co-9Al-9W (at%), was processed by mechanical alloying by high-energy milling of elemental powders and consolidated by field assisted hot pressing (FAHP). The milled powder particles mainly consist of undissolved bcc-W as well as WC and an Al and W rich fcc-gamma Co solid solution. After consolidation and heat treatment a fine grained microstructure with a high fraction of carbides and a gamma /gamma ' microstructure was obtained. The compressive yield strength at room temperature was found to be 45% higher than that of previously reported results for Co-based superalloys. A similar level of strength was found at 700 degrees C. These extraordinary properties can be explained due to the multitude of hardening mechanisms that sintered Co-based superalloys possess: gamma' precipitation, carbide formation and the ultra-fine se-grain size promoted by the fast consolidation technique.

keywords

  • Co-Al-W superalloys; PM route; Mechanical properties; Nanoindentation; Mechanical milling