Dislocation Density of FCC Metals Processed by ARB

Abstract

Accumulative roll bonding (ARB) was applied to three FCC metals, such as Al, Cu and Ni. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were made to evaluate dislocation density ρ of the ARB processed FCC metals. The values of ρ of ARB processed Cu and Ni increased rapidly after the first ARB cycle, and then, tend to saturate after the following cycles. The evaluated values of ρ of both ARB 8-cycled Cu and Ni using DSC were around 2×1015 m−2. Whereas, those using XRD were around 5×1014m−2 (for Cu) and 3×1014m−2 (for Ni). Although the ρ values depend on the measurement methods, the trends that DSC values are about an order of magnitude higher than XRD values seem to be common. In the case of Al, dislocation density evaluated using XRD increased to about 1×1013m−2 at the first ARB cycle, and then gradually decreased to about 1×1012m−2 with increasing number of ARB cycles.