Long range order in Ni/sub 3/Mo based ternary alloys-I. Isothermal aging response
In an attempt to understand the constitution of quaternary Ni-Al-Mo-X superalloys, the ordering reactions in Ni/sub 3/(Mo, X) alloys have been studied. The effects of additions of Al, Ta, V or W on the ordered structures produced during isothermal aging have been determined by transmission electron microscopy. Quenching the alloys from 1300/sup 0/C resulted in a f.c.c. matrix which exhibited diffuse diffraction intensity at the (1 1/2 0) locations of reciprocal space. Aging at 600, 700 and 800/sup 0/C caused various long range ordered structures to evolve from this matrix including Dla, DO/sub 22/ and Pt/sub 2/Mo prototype. The phases observed were depedent upon which ternary element was substituted for Mo. The diffraction evidence was consistent with a spinodal ordering transformation mechanism for all of the alloys aged at temperatures less than or equal to 700/sup 0/C. At 800/sup 0/C, the Al-bearing ternary formed the Pt/sub 2/Mo structure via a homogenous nucleation mechanism. These results are interpreted in terms of the statistical thermodynamic (pairwise interaction) theory as it has been applied to ordering systems.
- Research Organization:
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM
- OSTI ID:
- 5897824
- Journal Information:
- Acta Metall.; (United States), Vol. 32:10
- Country of Publication:
- United States
- Language:
- English
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ALUMINIUM ADDITIONS
METALLURGICAL EFFECTS
QUENCH AGING
ALUMINIUM ALLOYS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
TANTALUM ADDITIONS
TUNGSTEN ADDITIONS
VANADIUM ADDITIONS
AGING
CRYSTAL-PHASE TRANSFORMATIONS
DIFFRACTION
FCC LATTICES
HEAT TREATMENTS
HIGH TEMPERATURE
INTERMETALLIC COMPOUNDS
PLATINUM COMPOUNDS
TERNARY ALLOY SYSTEMS
THERMODYNAMICS
TRANSMISSION ELECTRON MICROSCOPY
VERY HIGH TEMPERATURE
ALLOY SYSTEMS
ALLOYS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELECTRON MICROSCOPY
MICROSCOPY
PHASE TRANSFORMATIONS
SCATTERING
TANTALUM ALLOYS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN ALLOYS
VANADIUM ALLOYS
360101* - Metals & Alloys- Preparation & Fabrication