Wear behavior of nanostructured Al/Al2O3 composite fabricated via accumulative roll bonding (ARB) process

An alternative method for manufacturing Al/B4C/SiC hybrid composite strips by cross accumulative roll bonding (CARB) process

“…But, some researchers have reported that the grain size measured by XRD (using Williamson-Hall method) is somewhat smaller compared to TEM (transmission electron microscopy) observations [25]. It has also been reported that dislocation reactions during deformation like dynamic recovery, decrease the cell size refinement [18]. The main role of the dynamic recovery is dislocation annihilation and since the rate of dynamic recovery is proportional to the material dislocation density, rate of dynamic recovery increases through straining and causes to decrease the rate of grain refinement at large strains.…”

“…The main role of the dynamic recovery is dislocation annihilation and since the rate of dynamic recovery is proportional to the material dislocation density, rate of dynamic recovery increases through straining and causes to decrease the rate of grain refinement at large strains. Structural refinement, observed in ARB and CARB processes can be explained in terms of grain subdivision at a submicron scale, where initial coarse grains are subdivided to smaller ones by deformation induced high angle grain boundaries [17,18]. Another reason for grain refinement is severe shear strain due to the friction between the strips and the rolling under dry condition.…”

“…The equivalent strain is increased by this shear deformation so that the grain refinement would be promoted. On the other hand, the B4C and SiC particles act as obstacles to the dislocation motion, thereby leading to the dislocation accumulation and to the formation of sub-grain and then grain boundaries [17,18,22,25]. The quality of bonding between the reinforcement and matrix and porosity are the other effective factors on MMCs properties.…”

“…4) Sheet elongation: Due to the sheet elongation, clusters of particles are aligned in the rolling direction (RD). This phenomenon leads to increasing the distance of particles, dissociation of clusters, the shrinkage of particle free zones and an improvement in the microstructure homogeneity [17,18]. During the ARB process, an amount of sheet elongation along rolling direction occurs which is a function of the reduction level.…”

“…The strips were degreased via acetone bath and brushed with a stainless steel wire brush having wire diameter of 0.26 mm (surface preparation). This has been stated as the best method for surface preparation by many authors [17,18]. The roll bonding process has been done by using a laboratory rolling mill, with a loading capacity of 20 tons, the roll diameter of 125 mm and the rolling speed of 35 rpm.…”