APFIM study of antiphase and grain boundaries in Ni/sub 3/Al

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5542725

Horton, J A; Miller, M K

Ni/sub 3/Al is an ordered intermetallic material and is potentially useful for high temperature applications. Unlike most alloys the yield stress of Ni/sub 3/Al actually increases with an increase in temperature. Unfortunately, pure Ni/sub 3/Al exhibits a brittle intergranular fracture and, consequently, low ductility. However, doping Ni/sub 3/Al with boron improves the mechanical properties and can result in room temperature ductilities up to 50% and a completely transgranular failure. Auger electron spectroscopy (AES) has shown that boron segregates to those boundaries which can be made to fail intergranularly and that no embrittling agents are found on fracture surfaces of pure Ni/sub 3/Al. Atom probe field-ion microscopy (APFIM) is an excellent technique to study the structure and chemistry of ''good'' boundaries, especially for light elements such as boron. Results from this study have shown that boron segregates to both grain boundries and antiphase boundaries (APB) and that a thin phase is usually present at the grain boundaries in rapidly solidified Ni/sub 3/Al.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5542725
• Report Number(s): CONF-860829-4; ON: DE86008494
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
BORON ADDITIONS
BORON ALLOYS
CRYSTAL STRUCTURE
DOPED MATERIALS
GRAIN BOUNDARIES
INTERMETALLIC COMPOUNDS
ION MICROSCOPY
MATERIALS
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
SEGREGATION