Production of nanograin microstructure in steel nanocomposite

Nanostructured AA5005/Al2O3 composite manufactured by anodising and accumulative roll bonding

“…The tensile strength of monolithic and composite increased from 105 MPa (for the annealed sample as the raw material) to 181 and 193 MPa after the first ARB cycle, registering 72.4% and 83.8% improve, respectively. The first ARB cycle has a remarkable influence on the tensile strength that is in good agreement with previous studies [3,4,6,7,16–24]. The values of tensile strength for the monolithic sample were 238, 279, and 291 MPa after third, fifth, and seventh cycles, respectively; while those for composite were 259, 313, and 336 MPa, respectively.…”

“…The ARB process differs from other severe plastic deformation processes in terms of the strengthening mechanisms. In addition to conventional strain hardening and grain refinement, there are some other mechanisms such as additional grain refinement due to severe shear deformation below the surface caused by high level friction between the sheet and the roll, redundant shear strain due to introduction of severely deformed material in the interior, introduction of new interfaces, and a uniform distribution of oxide film particles in the matrix and inclusions that prevent the movement of dislocations and also grain boundaries [6,16,17,[21][22][23]25]. The absence of these mechanisms is what makes the conventional rolling process quite inferior to ARB process.…”

“…Nanostructured and ultra-fine grained (UFG) composites are expected to be characterised as having high strength and toughness. In recent years, fabrication of nanostructured and UFG composites by accumulative roll bonding (ARB) process has received considerable interest as a technique for materials strengthening [6,16,17]. In addition, the ARB process has been shown to be an excellent method for particle distribution into a metallic matrix and a variety of metal matrix composites has been fabricated using this process [7,[18][19][20][21].…”

Inter-particle bonding in cold spray deposition of a gas-atomised and a solution heat-treated Al 6061 powder

“…The accumulation of dislocations around the secondary phases led to dynamic recrystallisation inside the particle, which reduced the number of dislocations in the particle-particle interfacial area due to a more homogeneous deformation throughout the particle. This phenomenon of localised dislocation accumulation has been also observed in cases of severe plastic deformation of various materials during processes such as equal channel angular pressing [46] or accumulative roll bonding [47]. The interaction of dislocation with precipitates and second-phase particles was thoroughly studied using TEM, where a high dislocation density was observed in their surrounding area [48].…”