CREEP TESTS OF ELECTRODEPOSITED NANOCRYSTALLINE Ni-W ALLOYS AT ELEVATED TEMPERATURES

Abstract. High-strength nanocrystalline Ni-W alloys containing about 16.9 at. % W with average grain sizes of about 6 nm in diameter have been obtained by electrodeposition. At room tempera-ture, the nominal tensile strength of the Ni-W alloy was attained to about 1600 MPa, while the plastic strain before fracture was a very low value of about 0.05%. In this case, highly localized shear bands were observed near the fractured surface of the tensile test specimen. When the samples were creep-tested at 300 °C for 120 h under the applied tensile stress of 326.7 MPa, plastic strain of about 0.7 % without the formation of localized shear bands was observed. 1