Plastic Deformation of Electrodeposited Nanocrystalline Ni-W Alloys at High Temperatures
High-strength nanocrystalline Ni-W alloys containing 16.9 at. % W with average grain size of about 6 nm in diameter has been obtained by electrodeposition. At room temperature, the nominal tensile strength of the alloy was attained to about 1600 MPa, while the plastic strain before fracture was a very low value of 0.05 %. In this case, highly localized shear bands were observed near the fractured surface of the tensile test specimen. When the samples were annealed at 300 °C under a static tensile stress of 327 MPa, the plastic strain was largely increased at the initial period of annealing and then tended to saturate, i.e., 0.54 % for 2 h, respectively. Grain size of the Ni-W alloys was almost saturated to 10 ~ 15 nm after annealing at 300°C for 2 h. It may be expected that the high tensile stress during grain growth might be effective to obtain the large uniform plastic deformation of nanocrystalline Ni-W alloys.
Young Won Chang, Nack J. Kim and Chong Soo Lee
H. Yokoyama et al., "Plastic Deformation of Electrodeposited Nanocrystalline Ni-W Alloys at High Temperatures", Materials Science Forum, Vols. 561-565, pp. 1295-1298, 2007