Porous NiTi with an average porosity of 55 vol % and a general pore size of 100-600 microm was synthesized by self-propagating high temperature synthesis (SHS) with the addition of mechanically alloyed nanocrystalline Ni-Ti as the reaction agent. The SHS of porous NiTi using elemental powders was also performed for comparison. To enhance the bioactivity of the metal surface, porous NiTi synthes...

We have conducted highP-Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume-pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced over...

Nanocrystalline partially stabilised zirconia (PSZ) and yttria-fully stabilised zirconia (YSZ) powders were prepared by solution combustion process. Nanocrystalline nature of the powders was confirmed by XRD and TEM. Nanocomposite Ni/PSZ and Ni/YSZ films were electrodeposited from a suspension of nanoparticles in nickel sulfamate solution. The strengthening of the nanocomposite due to nanoparti...

ni-w coatings, compared to pure nanocrystalline ni, exhibit higher hardness and wear resistance. in some cases, these coatings are considered as environmental friendly alternatives for hard chromium coating. till now, most of ni-w coatings have been produced by direct current electrodeposition from alkaline baths. in this study square pulse current was used for deposition of ni-w precipitates f...

Nanocrystalline materials have experienced a great deal of attention in recent years, largely due to their impressive array of physical properties. In particular, nanocrystalline mechanical behavior has been of interest, as incredible strengths are predicted when grain size is reduced to the nanometer range. The vast majority of research to this point has focused on quantifying and understandin...

Solid solution strengthening in nanocrystalline alloys is studied using sputtered Ni–W as a model system. In the composition range of 0–20 at.% W, the sputtered alloys have a nanocrystalline structure with a grain size that is independent of composition. Nanoindentation of these alloys shows that solute addition increases strength to very high levels, almost in proportion to the solute content....

Ni-W coatings, compared to pure nanocrystalline Ni, exhibit higher hardness and wear resistance. In some cases, these coatings are considered as environmental friendly alternatives for hard chromium coating. Till now, most of Ni-W coatings have been produced by direct current electrodeposition from alkaline baths. In this study square pulse current was used for deposition of Ni-W precipitates f...

High-density (>98% of full density) nanocrystalline invar alloys with significantly enhanced hardness (>240 in Vicker’s hardness) were prepared by sintering compacted Fe-Ni nanoparticles in hydrogen. The precursor Fe-Ni nanoparticles were synthesized by hydrogen plasma evaporation of bulk Fe61Ni39 alloys. The size and the productivity of the Fe-Ni nanoparticles increased with increasing hydroge...

The mechanisms of stress-assisted grain growth are explored using molecular dynamics simulations of nanoindentation in nanocrystalline Ni and Ni-1 at.% P as a function of grain size and deformation temperature. Grain coalescence is primarily confined to the high stress region beneath the simulated indentation zone in nanocrystalline Ni with a grain size of 3 nm. Grain orientation and atomic dis...

Mechanical alloying of Ti-Si and NiTi was performed by high-energy ball milling at ambient temperature. The structural and compositional evolutions during mechanical alloying were investigated. Results showed that the crystallite size of mechanically alloyed Ti-Si and Ni-Ti powders decreased with increasing milling time and the steady-state crystallite size was approximately 10 nm. The mechanic...