A contemporary view of nickel-base superalloys

Survey of degradation modes of four nickel-chromium-molybdenum alloys

“…The TiC because of its 0.7 wt% titanium addition.) This concentration of sulfur, on the other hand, goes through carbide is fcc with lattice parameters much larger than a local maximum near 300°C, but after a minimum at those of the host lattice (Sims 1966). Carbides of M6C…”

“…(The authors suggest that the extersolution-annealed specimens. These carbide phases are nal surface behavior may reflect the grain-boundary called "primary" precipitates (Sims 1966) to distinguish behavior of the alloy.) The study was performed at temthem from other phases that precipitate after aging at peratures between 100 and 900°C.…”

Effect of Solution-Treatment on Microstructure and Mechanical Properties of Cast Fine-Grain CM 247 LC Superalloy

“…The fine carbide particles at the grain boundaries may reduce the mobility of the grain boundaries and absorb the energy of deformation, hence both the ultimate tensile strength and the total elongation initially increase with the dissolution temperature. Moreover, Sims 24) indicated that coarse 0 and -0 depletion near the grain boundary in high strength nickel alloys may also form a ductile zone, preventing the initiation of grain-boundary fracture through enhanced the local ductility. However, increasing the dissolution temperature from 1494 K/2 h to 1533 K/2 h reduces the size of the ductile zone (Fig.…”

Microstructure of Nickel‐Based Superalloys

“…To the authors' knowledge detailed studies of the composition of o in nickel-based superalloys have not been performed. However, it is believed that (T in such alloys is rich in Cr, Mo, Ni, and Go, and that it can be represented by (Cr, Mo),(Ni, Co),, where x and y can vary from 1 to 7 [33].…”

“…However, in cast alloys containing these carbides in a dendritic script-like morphology, one would expect the tips of the carbide dendrites to be regions of high stress concentration. Indeed, evidence is available which suggests the script-like carbides to serve as crack nucleation sites under fatigue testing conditions [33]. Perhaps a more important feature of the MC carbide than its effects on mechanical properties per se is its decomposition to y' and the more complex carbide M,,C, according to the following reaction :…”