Phase stability and alloy design of ordered intermetallics

Conference · Thu Jan 01 00:00:00 EST 1987

OSTI ID:5251951

Liu, C T

Recent research on phase stability and grain boundary structure in ordered intermetallics is summarized. Ordered intermetallics have many attractive high-temperature properties;however, low ductility and brittle fracture limit their use for structural applications. Embrittlement in intermetallics is mainly caused by low-crystal symmetry and insufficient number of slip systems, poor cleavage strength, and intrinsic and extrinsic grain-boundary weakness. Experimental studies of ordered phase stability and grain-boundary structure have led to substantial improvement in the ductility and fracture toughness of several ordered intermetallics, including (Co,Fe)/sub 3/V, (Ni,Fe)/sub 3/V, (Co,Ni,Fe)/sub 3/V, Fe/sub 3/Al, Ni/sub 3/Al, Ni/sub 3/Ga, and Ni/sub 3/Si. At present, the control of ordered structures and grain-boundary properties is mainly based on some empirical andor phenomenological relationship. First-principles calculations have advanced to the stage that they are able to help us to understand the electron structure and phase stability and to design ductile ordered intermetallic alloys for structural use at elevated temperatures. 64 refs., 11 figs., 1 tab

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5251951
• Report Number(s): CONF-8706103-8; ON: DE88007479
• Resource Relation: Conference: NATO advanced study institute on alloy phase stability, Crete, Greece, 14 Jun 1987; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
INTERMETALLIC COMPOUNDS
GRAIN BOUNDARIES
MECHANICAL PROPERTIES
REVIEWS
STABILITY
ALUMINIUM ALLOYS
BORON ADDITIONS
COBALT ALLOYS
CRYSTAL DOPING
CRYSTAL STRUCTURE
DISLOCATIONS
DUCTILITY
ELECTRONIC STRUCTURE
EMBRITTLEMENT
FRACTURE PROPERTIES
GALLIUM ALLOYS
IRON ALLOYS
NICKEL ALLOYS
NICKEL SILICIDES
ORDER PARAMETERS
VALENCE
VANADIUM ALLOYS
ALLOYS
BORON ALLOYS
CRYSTAL DEFECTS
DOCUMENT TYPES
LINE DEFECTS
MICROSTRUCTURE
NICKEL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
TENSILE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360102* - Metals & Alloys- Structure & Phase Studies
360103 - Metals & Alloys- Mechanical Properties