Recovery and recrystallization of the deformed, orderable alloy (Co sub 78 Fe sub 22 ) sub 3 V

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1991.0057· OSTI ID:5676500

Cahn, R W ^[1]; Takeyama, M; Horton, J A; Liu, C T ^[2]

---

1. Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom (GB)
2. Metals and Ceramics Division, Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge, Tennessee 37831-6115 (USA)

An alloy of composition (Co{sub 78}Fe{sub 22}){sub 3}V, which orders to an Ll{sub 2} superlattice below a critical temperature ({ital T}{sub {ital c}}) of 910 {degree}C, was rolled to 25--50% reduction in the initially ordered condition and annealed at various temperatures above and below {ital T}{sub {ital c}} and examined by hardness, tensile testing, optical and electron microscopy and dilatometry, in order to study the progress of recovery and recrystallization. Recrystallization was severely retarded on annealing below {ital T}{sub {ital c}}; close to {ital T}{sub {ital c}}, recrystallization was {approx}300{times} slower in the ordered than the disordered range. Although recrystallization started promptly, predominantly at grain boundaries, very rapid recovery-softening of the unrecrystallized regions progressively reduced the driving force for recrystallization and slowed it down drastically. However, at 770{degree} and 500 {degree}C, recovery-softening was replaced by some recovery-hardening (i.e., strain-age hardening). Above {ital T}{sub {ital c}}, recrystallization was complete in a few seconds and a special annealing method was needed to measure such times accurately. Dilatometric measurements showed that most of the order destroyed by rolling was restored long before recrystallization began, but the restoration was never complete unless the alloy was heated up through {ital T}{sub {ital c}} and then slow cooled. Electron microscopy showed no sign of any antiphase domains in recrystallized grains except for a few isolated domain boundaries on annealing at 770 {degree}C. A model is proposed to rationalize the incidence of recovery-softening or strain-age hardening at different annealing temperatures.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5676500
• Journal Information: Journal of Materials Research; (USA), Vol. 6:1; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT BASE ALLOYS
RECOVERY
RECRYSTALLIZATION
IRON ALLOYS
AGE HARDENING
ANNEALING
CRITICAL TEMPERATURE
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
GRAIN BOUNDARIES
HIGH TEMPERATURE
MATERIALS WORKING
ROLLING
STRAIN HARDENING
SUPERLATTICES
TENSILE PROPERTIES
VANADIUM ADDITIONS
VERY HIGH TEMPERATURE
ALLOYS
COBALT ALLOYS
CRYSTAL STRUCTURE
DATA
FABRICATION
HARDENING
HEAT TREATMENTS
INFORMATION
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
NUMERICAL DATA
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VANADIUM ALLOYS
360101* - Metals & Alloys- Preparation & Fabrication
360102 - Metals & Alloys- Structure & Phase Studies