Technologies Company Sprayforming is a promising route for production of highly segregation prone alloys such as the high y' fraction nickel alloys that are finding increased usage in the hot stages of aircraft turbines. Conventional ingot metallurgy (IM) is experiencing increasing difficulties with segregation and segregation-related defects such as freckles and white spots with the highly alloyed materials and probably will not be able to produce the next generation of hot stage alloys. Powder metallurgy (PM) is an expensive production route and the oxide cleanliness is inferior to IM. Sprayforming offers the segregation free microstructure of PM with the oxide cleanliness of IM through the clean metal sprayforming (CMSF) technique at a production cost intermediate between IM and PM. Sprayformed Allvac@ 720 Alloy was produced by nitrogen gas atomization and collected as 325 mm diameter billets. The nitrogen atomization eliminated the thermal induced porosity typical of powder metallurgy production using argon atomization and refined the initial structure relative to conventional cast material. The as-sprayed grain size is an equiaxed ASTM 6-7 and the carbonitride particle distribution is l-2 urn. No segregation or segregation-related defects such as freckles or white spots were observed. The response of sprayformed material to thermomechanical processing (TMP) is demonstrated by an experimental forging matrix measuring the effects of heat treatment, strain, and strain rate. The sprayformed material exhibits a strong recrystallization response and the only unrecrystallized grains are observed in low strain rate deformation conditions. The deformation temperature and strain rate are the primary variables affecting the flow stress and the prior heat treatment has a minor effect at lower temperatures in the hot working range.
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