Ultrafine-grained (UFG) Ti for improved mechanical performance as well as its surface modification enhancing biofunctions has attracted much attention in medical industries. Most of the studies on the surface etching of metallic biomaterials have focused on surface topography and wettability but not crystallographic orientation, i.e., texture, which influences the chemical as well as the physic...

For testing time-dependent material properties by nanoindentation, in particular for long-term creep or relaxation experiments, thermal drift influences on the displacement signal are of prime concern. To address this at room and elevated temperatures, we tested fused quartz at various contact depths at room temperature and ultra-fine grained (ufg) Au at various temperatures. We found that the ...

Commercially pure nickel was processed by equal channel angular pressing (ECAP) through route Bc for 12 passes to obtain an ultrafine grained (UFG) microstructure and further subjected to an ultrasonic treatment (UST) which introduced a maximum amplitude equivalent to anormal stresses of 100 MPa in a steady state regime. It was observed that the microstructure of UFG Ni can be differently alter...

A dislocation bow-out model has been developed to explain the strength of ultra-fine grained (UFG) materials with grain size roughly between 20 nm to 500 nm. In the model, perfect dislocations are assumed to be nucleated at grain-boundary sources and bow out between two pinning points on a boundary. Yielding is considered to occur when a dislocation takes a semi-circular shape under applied str...

To gain insight into the origin of the ultra-high strength of ultrafine-grained (UFG) alloys, the solute clustering, precipitation phenomena, and microstructural evolutions were studied in an UFG Al-4.63Cu-1.51Mg (wt.%) alloy (AA2024) processed by high-pressure torsion (HPT). The thermal analysis was performed using differential scanning calorimetry. The microstructures, internal microstrains a...

Ultrafine-grained (UFG) pure copper of 280 nm grain size was prepared by equal-channel angular pressing. Tensile tests, strain-rate change tests and temperature change tests were conducted on UFG Cu in the temperature range between 77K and 373K. As usual, tensile strength increased as temperature decreased and strain rate increased. The activation energy of deformation increased linearly with t...

It is shown that thermomechanical treatment (TMT) of the EK61 superalloy with a strain rate (ε∙) 10−3 s−1 and gradual decrease in temperature from (0.92 – 0.65)Tδ leads to transformation initial coarse-grained structure into an ultrafine-grained (UFG) mixed type structure. Such UFG microstructure consists γ-phase grains δ-phase particles 0.3 μm size relatively large up 2 size. The having such e...

severe plastic deformation (spd) methods were developed for producing of metals and alloys with ultrafine grained (ufg) microstructures having high strength. parallel tabular channel angular pressing (ptcap) as a noble severe plastic deformation (spd) method was used to produce ultrafine grained (ufg) and nanostructured cu-30%zn tubes. in this paper, the effect of ptcap process temperature on t...

In the last three decades, several severe plastic deformation (SPD) procedures have been developed and applied in materials science to create bulk, ultrafine-grained (UFG) structures. As a consequence of SPD, not only submicron even nanometer grain sizes can be obtained, but also new boundaries with non-equilibrium structures material may formed. Therefore, both strength ductility UFG change si...

In this paper, the fracture kinetics and mechanisms in low-cycle fatigue region were analyzed for different ultrafine-grained (UFG) materials with body-centered cubic (bcc), hexagonal close-packed (hcp) face-centered (fcc) lattices. Three-point bending principle tests performed. The show that UFG structure formation investigated has an ambiguous effect on total number of cycles to failure (life...