Microstructure stability and hardening determination through heat treatment of sintered Co gamma/gamma" based alloys Articles uri icon

publication date

  • October 2021

start page

  • 242

end page

  • 252

issue

  • 3

volume

  • 65

International Standard Serial Number (ISSN)

  • 0032-5899

Electronic International Standard Serial Number (EISSN)

  • 1743-2901

abstract

  • Aiming to improve gamma´ volume fraction through alloying elements and heat treatments, the influence of the combined effect of 2 Ti and 2 Ta addition (at%) to a nominal Co-12Al-10W at.% Co-based superalloy, and the heat treatments parameters have been investigated. The Co-based alloys were manufactured by PM using mechanical alloying for powder processing, and a field-assisted sintering technique to consolidate the material. The specific study of solution temperatures and ageing times to promote the gamma/gamma´ dual-phase was carried out through a complete microstructural analysis and micro and nano hardness measurements. The composition of the gamma (fcc)-matrix and gamma´ (L12)-precipitates, the nanoscale properties including gamma´; volume fraction and gamma/gamma´ misfit were measured as a function of increasing solution and ageing time. In the end, Ti and Ta addition to the Co-12A-10W alloy increases gamma´ volume fraction and thermal stability for long ageing time detecting slow coarsening.

subjects

  • Materials science and engineering

keywords

  • co-based superalloys; solution; heat treatment; volume fraction; field-assisted sintering techniques