Disordering phase transformation in (Ni/sub 70/Fe/sub 30/)/sub 3/(V/sub 98-x/Al/sub x/Ti/sub 2/) alloys with 0 less than or equal to x less than or equal to 80

Conference · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5987827

DasGupta, A; Horton, J A

The sequence of disordering transformation processes in the A/sub 3/B type alloy series (Ni/sub 70/Fe/sub 30/)/sub 3/(V/sub 98-x/Al/sub x/Ti/sub 2/), currently under development for high-temperature structural applications, was studied by differential scanning calorimetry (DSC), x-ray diffraction, optical microscopy, and transmission electron microscopy (TEM). Results of DSC show that in all alloys there are two endothermic stages of phase transformation from the ordered to the disordered state. With increasing x, the disordering transition temperature, T/sub c/, reaches a maximum approx.1000/sup 0/C at x approx. = 50, and then decreases. Interrupted heating, followed by water quenching, was used to characterize the crystal structure and the microstructure of the intermediate phases. For the x = 20 alloy, TEM observations showed ordered regions of DO/sub 22/ phase in a matrix of disordered fcc(Al) phase at intermediate temperatures. The ordered domains transformed morphologically into cuboid like regions at higher temperatures. From a combined study by all the techniques, in alloys with x between 0 and 20, the sequence of phase transformations upon heating is: DO/sub 22/ ..-->.. DO/sub 22/ + Al ..-->.. Al, whereas in alloys with greater than or equal to 40, the major sequence is /sub 2/ + B2 ..-->.. L1/sub 2/ + Al ..-->.. Al.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5987827
• Report Number(s): CONF-841157-102; ON: DE86002186
• Resource Relation: Conference: Materials Research Society annual meeting, Boston, MA, USA, 26 Nov 1984; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
ORDER-DISORDER TRANSFORMATIONS
NICKEL ALLOYS
TITANIUM ALLOYS
VANADIUM ALLOYS
CALORIMETRY
ELECTRON MICROSCOPY
INTERMETALLIC COMPOUNDS
IRON ALLOYS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
ALLOYS
COHERENT SCATTERING
DIFFRACTION
MICROSCOPY
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SCATTERING
THERMODYNAMIC PROPERTIES
360102* - Metals & Alloys- Structure & Phase Studies