Microstructure Evolution of Primary γ′ Phase in Ni3Al-Based Superalloy

A new dental superalloy system. 3. Microstructure and phase transformations.

A microstructural study was conducted on 15 cobalt-chromium-nickel alloys of the basic composition 40 Co-30 Ni-30 Cr. The alloys were strengthened by the addition of tantalum and tantalum-rich regions were found at the interdendritic spaces. The increase in Ta concentration caused a decrease in the concentration of the a phase and an increase in the amounts of the a phase. Excessive amounts of ...

Influence of the initial cooling rate from γ’ supersolvus temperatures on microstructure and phase compositions in a nickel superalloy

Different cooling paths from a supersolvus temperature have been applied to FGH96, a polycrystalline nickel base superalloy for turbine disc applications, in order to simulate the different microstructures that exist through the thickness of a disc following an industrial heat treatment. Secondary and tertiary γ’ precipitate size distributions and morphology have been analysed and compared for ...

Tem-studies of the dislocation structure in a γ/γ’ Ni-based superalloy

Dependence of Creep Performance and Microstructure Evolution on Solution Cooling Rate in a Polycrystalline Superalloy

It is well known that the solution cooling rate has a great effect on the creep life of superalloys. In this research, three typical cooling rates were applied to generate different distributions of γ’ precipitates for creep tests. Ingots used to make specimens were manufactured by hot extrusion, and the master alloy had the composition of an FGH4096 power metallurgy superalloy. SEM and SESD we...

EFFECT OF COMPOSITION ON PHASE EVOLUTION AND MICROSTRUCTURE OF REACTION BONDED MULLITE (RBM)

Compositions of Al2O3+Si, SiO2+Al and Al+Si systems were prepared to study the effect of reaction bonding process on the mullite formation. The composition of each system was adopted according to mullite stoichiometery and sintered in 700-1600°C range. Results showed that the formation of reaction bonded mullite starting from Al2O3+Si mixtures, proceeded in two partially overlapping steps, the ...