Strengthening in a DS casting Ni3Al base alloy IC6

A unidirectionally solidified casting gamma' base alloy IC6, with the chemical composition (at.%) 16.3-17.6% Al, 8.0-8.3% Mo, 0.16-0.78% B, Ni balance has been developed for advanced gas turbine blades and vanes. The experimental results show that this alloy has high yield strengths from room temperature to 1100 degrees C, excellent creep resistance at temperatures up to 1100 degrees C. The microstructural observations and analysis indicate that the superior mechanical properties of this alloy may be attributed to solid solution hardening by the large molybdenum addition, second phase strengthening by gamma' phase and other minor phases that precipitate in various temperature ranges, the formation of a gamma raft structure during creep, and to the existence of high density misfit dislocation networks at gamma'/gamma interface areas due to a high value of gamma'/gamma misfit.