Intergranular fracture and boron effects in Ni sub 3 Al and other intermetallics; Introductory paper

Journal Article · Sat Jun 01 00:00:00 EDT 1991 · Scripta Metallurgica; (United States)

OSTI ID:5429492

Liu, C T ^[1]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

This paper reports that recently, considerable research effort has been concentrated on the study of intergranular fracture and ductility improvement in Ni{sub 3}Al. Among the reasons for selection of Ni{sub 3}Al as a model material include grain boundaries (GBs) in Ni{sub 3}Al are intrinsically brittle, microalloying of boron in the ppm range suppresses GB fracture and dramatically improves tensile ductility at ambient temperatures, and Ni{sub 3}Al shows the yield anomaly behavior and excellent high-temperature strength for potential structural applications. This concentrated effort has led to substantial advance in our understanding of intergranular fracture and microalloying effects in Ni{sub 3}Al and other L1{sub 2} intermetallics, including Ni{sub 3}Si, Ni{sub 3}Ga, and NiGe. Currently, the study of GB fracture has extended to B2-type intermetallics such as NiAl and FeAl. There is , however a lack of general consensus in several areas, and the most prominent one is the little agreement on the mechanism responsible for the ductilizing effect of boron in Ni{sub 3}Al. A mechanistic understanding of the boron effect requires a detailed knowledge of GB chemistry and structure, both of which are very complex and sensitive to a number of factors, such as local chemical order, alloy stoichiometry, boron segregation, GB character, and GB/dislocation interactions.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5429492
• Journal Information: Scripta Metallurgica; (United States), Vol. 25:6; ISSN 0036-9748
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
DUCTILITY
GRAIN BOUNDARIES
NICKEL BASE ALLOYS
BORON ADDITIONS
FRACTURE PROPERTIES
HEAT RESISTING ALLOYS
INTERGRANULAR CORROSION
INTERMETALLIC COMPOUNDS
ORDER-DISORDER TRANSFORMATIONS
RESEARCH PROGRAMS
TEMPERATURE RANGE 0400-1000 K
YIELD STRENGTH
ALLOYS
BORON ALLOYS
CHEMICAL REACTIONS
CORROSION
CRYSTAL STRUCTURE
HEAT RESISTANT MATERIALS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
PHASE TRANSFORMATIONS
TEMPERATURE RANGE
TENSILE PROPERTIES
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies
360105 - Metals & Alloys- Corrosion & Erosion