Fracture toughness, wear, and microstructure properties of aluminum/titanium/steel multi-laminated composites produced by cross-accumulative roll-bonding process

For more than a decade many researchers have been developing new ways to produce laminated composites. In this paper, aluminum/titanium/steel multi-laminated composites were fabricated by the cross accumulative roll bonding (CARB) process, and effects of different rolling passes on microstructure, and mechanical properties were investigated. As the number of rolling passes increased, in spite of having no voids and cracks, more instabilities were observed on titanium and steel layers. With regard to mechanical properties, by increasing the rolling passes, the values of ultimate and yield strength, as well as elongation fell, because of the non-uniform distribution of hard layers within the aluminum matrix. Based on scanning electron microscopy (SEM) images, both ductile and cleavage modes of fracture were observed on fracture surfaces. Furthermore, with an increase in the number of rolling passes, the values of fracture toughness pertaining to the crack initiation declined on account of the increased probability of delamination. Plus, the trend of the R-curves was mainly downward due to the growing number of interfaces within the matrix by increasing the number of passes; nonetheless, the upward trend of these curves may be attributed to the ductile Al matrix in which the path of cracks can be bridged. Also, based on the results of wear tests, different wear mechanisms such as adhesion, abrasion, and delamination were observed, and with an increase in the number of rolling passes, the amount of weight loss showed a decline which was due to the rise of hardness concerning the strain-hardened layers.