Composite rods by high-temperature gas extrusion of steel cartridges stuffed with reactive Ni–Al powder compacts: Influence of process parameters

• Published in: Intermetallics Vol. 138; p. 107317
• Main Authors: Galiev, F.F., Saikov, I.V., Alymov, M.I., Konovalikhin, S.V., Sachkova, N.V., Berbentsev, V.D.
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.11.2021; Elsevier BV
• Subjects: Aluminum; Cartridges; Combustion synthesis; Compacting; Composite materials; Composite rods; Extrusion cladding; High temperature gases; Hot gas extrusion; Intermetallic compounds; Intermetallics; Iron; Nickel aluminides; Nickel base alloys; Nickel compounds; Ni–Al system; Powder compacts; Process parameters; Rods; SHS; Steel clad rods; Steel products; Combustion synthesis; Hot gas extrusion; Composite rods; Intermetallics; Steel clad rods; Ni–Al system; SHS
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2021.107317

Steel clad NiAl rods were prepared by high-temperature gas extrusion (HTGE) of steel cartridges stuffed with reactive Ni–Al powder compacts upon variation in warmup temperature Tw (600–780 °C) and gas (Ar) pressure P (200–480 MPa). A largest amount of NiAl and Ni3Al intermetallics in rod core was obtained at Tw = 780°С and P = 200 MPa. For Tw < 660°С (m.p. of Al), the rod core was found to contain significant amounts of unreacted Al and Ni. A transition zone of Al–Fe intermetallics (10 μm thick) was found only in the rod obtained at Tw = 780°С and P = 200 MPa. The core material of such rods exhibited a largest mean value of hardness (1050 HV). It is suggested that the yield of target intermetallics can be improved by using charge compacts prepared from mechanically activated Ni–Al blends. Combined use of (a) in-situ synthesis of target product in a core and (b) extrusion of the entire fixture seem promising for fabrication of composite materials with unique properties. •For the first time, hot gas extrusion was combined with combustion synthesis.•This technique was used to fabricate steel clad intermetallic rods.•Influence of gas extrusion parameters on the properties of rod core was explored.•Composition of rod core can be adjusted by proper choice of process parameters.•Our approach opens up new horizons for fabricating functional and structural materials.