# Accumulative Roll Bonding--A Review
## 3 Parameters
### Rolling Parameters
#### 3.3.6 Reinforcement Particles  
From a perspective, the sheets produced by ARB, can be divided into monolithic, composite and metal matrix composite (MMC) forms; the latter is usually produced with the addition of reinforcing agents. Using ARB, MMCs can be produced by uniform distribution of strengthening additives between the sheets. The effect of these additives in terms of shape, geometry, size, material, and volume fraction can be investigated. [PERSON] and [PERSON] (2018) studied the effects of SiC particles on the mechanical properties of Al strips. At first, they used a peeling test to find out the effect of carbide particles on the bond strength and also to measure the minimum reduction required for achieving an acceptable bond between the two strips. For one-cycle ARBed specimens, their results are presented in Figure 8a,b. The results show that SiC decreases peeling force at constant reduction since SiC prevents the extrusion of virgin material through interfacial cracks; therefore, bonding area and consequently bond strength decreases. As a result, while using SiC, the bonding is not successful unless thickness reduction is sufficiently high, i.e., 66% (with SiC) and 50% (without) reductions in thickness are required. In addition, their results showed that reinforcement would reduce the bond strength in the first ARB cycle. Shown in Figure 8c,d, it was concluded that the UTS of the Al/SiC\({}_{\text{P}}\) metal matrix composite can be improved by increasing the number of rolling cycles up to seventh cycle; it is then saturated for higher cycles. The microstructural evaluation indicates that by increasing the number of cycles, the uniformity of SiC particles increases and porosity decreases. Another observation made by researchers was that the Al/SiC\({}_{\text{P}}\) composite specimen exhibit lower strength than the monolithic one before three ARB cycles, which confirms the fact that for an acceptable composite production using ARB a minimum number of cycles is necessary to decrease the amount of porosity and to reach a balanced distribution of particles in the metal matrix. Although SiC addition had a positive effect on the strength of ARBed specimens, the elongation to failure decreased. Figure 7: Changes in mechanical properties with annealing temperature of IF steel processed by three cycles of six-layer stack ARB compared to the results of a two-layer one ([PERSON] et al., 2018). [PERSON] and [PERSON] [54] examined the effect of alumina particles on the Rt of pure Al sheets (Figure 9). They indicated that Rt increases to 45% in the presence of the alumina particles compared with the Rt of 20% being needed for the bonding of Al sheets under the same conditions attributing it to the friction coefficient reduction and the need for longer channel extrusion of virgin metal surfaces through the cracks in the presence of a powder layer. [PERSON] and [PERSON] [55] investigated the effect of volume fraction on the strength of MMCs produced by ARB for pure Al reinforced by different weight percentages of anodized Al strips. Besides the strength enhancement provided by the SPD, mechanical strength could be significantly improved by reinforcing alumina particles used in the host material. It should be noted that strain hardening and dislocation strengthening play a key role in strength enhancement for ARBed monolithic specimens. For the reinforced ARBed MMC specimens, the particles act as a barrier against dislocation movement and crack growth. Similar result for the enhanced strength with increasing volume fraction of particles has been reported in all researches conducted on the ARB produced composites [56; 57; 58]. [PERSON] et al. [56] showed that after increasing the volume fraction of tungsten by 2.8%, further increase in strength is not realized [59].