Effects of boron on the toughness of {gamma}-{gamma}{prime} nickel aluminium superalloys

Journal Article · Fri Dec 04 04:00:00 EST 1998 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(98)00380-7· OSTI ID:305410

Chiu, Y L; Ngan, A H.W. ^[1]

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1. Univ. of Hong Kong (Hong Kong). Dept. of Mechanical Engineering

The ordered L1{sub 2}-type intermetallic Ni{sub 3}Al ({gamma}{prime}) possesses outstanding high-temperature mechanical properties. Single crystals of Ni{sub 3}Al are ductile when tested in ambient conditions, but the ductility in polycrystalline state is very poor due to grain boundary failure. This problem has been well solved with a small amount of boron addition (0.5 to {approximately}1.0 at %), which significantly toughens the material. Compared to pure Ni{sub 3}Al, the effects of boron doping on two-phase {gamma}-{gamma}{prime} alloys has not been thoroughly investigated. It has been shown that boron partitions to the grain boundaries of nickel-based superalloys and forms boride there which will stabilize the grain size at elevated temperatures, but the role of boron in influencing the toughness and grain boundary microstructures of the superalloy is not clear. In particular, it would be very interesting to know whether the toughening and nickel co-segregation behavior of boron in the pure {gamma}{prime} situation will extend to the two-phase {gamma}-{gamma}{prime} system. In this paper the authors will report some effects of boron on {gamma}-{gamma}{prime} alloys, and in order to remove any effects of other elements usually added to superalloys, boron is the only addition here.

• OSTI ID: 305410
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 1 Vol. 40; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BORON ADDITIONS
FRACTURE PROPERTIES
GRAIN BOUNDARIES
INTERMETALLIC COMPOUNDS
METALLURGICAL EFFECTS
NICKEL ALLOYS