Environmental embrittlement: A major cause for low ductility of ordered intermetallics

Conference · Thu Dec 07 00:00:00 EST 1989

OSTI ID:5070647

Liu, C T; McKamey, C G

This paper provides a brief review of recent research on the effect of test environment on ductility and fracture in ordered intermetallics. A number of intermetallics including FeAl, Fe{sub 3}Al, Co{sub 3}Ti and Ni{sub 3}Al alloys show distinctly room- temperature lower ductilities when tested in air than in vacuum or controlled environments. The environmental embrittlement involves the reaction of water vapor in the air with reactive elements (such as aluminum) in the intermetallics and the resulting generation of atomic hydrogen that drives into the metals and promotes brittle fracture along grain boundaries or cleavage planes. It has been demonstrated that, in some alloy systems, the embrittlement can be alleviated or totally eliminated by alloying additions. The test environment can also affect the ductility of ordered intermetallics at elevated temperatures, but the embrittling mechanism and agent are quite different. The study of environmental effects has led to better understanding of brittle fracture and low ductilities, thereby providing a new direction for alloy design of ductile ordered intermetallics for structural use. 72 refs., 13 figs., 2 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5070647
• Report Number(s): CONF-8910117-1; ON: DE90006161
• Resource Relation: Conference: Conference on high temperature aluminides and intermetallics, Indianapolis, IN (USA), 1-5 Oct 1989
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
EMBRITTLEMENT
COBALT BASE ALLOYS
NICKEL BASE ALLOYS
TITANIUM ALLOYS
CHEMICAL REACTIONS
CRYSTAL LATTICES
DUCTILITY
ELONGATION
INTERMETALLIC COMPOUNDS
STRAIN RATE
TENSILE PROPERTIES
YIELD STRENGTH
ALLOYS
COBALT ALLOYS
CRYSTAL STRUCTURE
MECHANICAL PROPERTIES
NICKEL ALLOYS
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies