Properties of the Ir{sub 85}Nb{sub 15} two-phase refractory superalloys with nickel additions

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0303-6· OSTI ID:20002007

Gu, Y F; Yamabe-Mitarai, Y; Ro, Y; Yokokawa, T; Harada, H

The effects of nickel content on the properties of the polycrystalline Ir{sub 85}Nb{sub 15} refractory superalloy were studied. To examine the possibility of replacing Ir with Ni in Ir{sub 85{minus}N}Nb{sub 15}Ni{sub X}, the authors varied the nickel content from 0 to 50 at. pct. The yield strength of the Ir{sub 75}Nb{sub 15}Ni{sub 10} alloy was 2,150 MPa at room temperature, much greater than that of the binary Ir{sub 85}Nb{sub 15} alloy, and 728 MPa at 1473 K, similar to that of the binary alloy. The fracture mode of an Ir{sub 85{minus}X}Nb{sub 15}Ni{sub X} alloy changed from predominantly intergranular in fcc and L1{sub 2} two-phase Ir{sub 85}Nb{sub 15} to transgranular in the two-phase Ir{sub 75}Nb{sub 15}Ni{sub 10} alloy and a mixture of intergranular and transgranular in the other tested alloys when the Ni content exceeded 20 pct. The Ni addition also increased the compression ductility for Ni content up to 50 at. pct. The maximum compression ductility was approximately 13 pct, obtained from Ir{sub 65}Nb{sub 15}Ni{sub 20}. Ir{sub 85{minus}X}Nb{sub 15}Ni{sub X} two-phase refractory superalloys with X {le} 10 were superior to the binary IR{sub 85}Nb{sub 15} alloy as an ultra-high-temperature structural material in terms of strength, fracture behavior, and density.

• Research Organization: National Research Inst. for Metals, Ibaraki (JP)
• OSTI ID: 20002007
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 10 Vol. 30; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BULK DENSITY
CHEMICAL COMPOSITION
COMPRESSION STRENGTH
FRACTURE PROPERTIES
INTERMETALLIC COMPOUNDS
IRIDIUM ALLOYS
METALLURGICAL EFFECTS
NICKEL ALLOYS
NIOBIUM ALLOYS
YIELD STRENGTH