Annealing Texture of Nanostructured Steel-Based Nanocomposite

Abstract

In this research, the evolution of annealing texture in nanostructured steel-based nanocomposite fabricated via accumulative roll bonding (ARB) process was investigated. Textural evolution after post-annealing of ARB-processed samples was evaluated using x-ray diffraction. Average grain size of the sample before and after the post-annealing was 55 nm and 1.5 lm, and the microstructures were uniform. All the samples indicated a strong a-fiber and c-fiber and a relatively weak f-fiber. Also, there were texture transitions in the a-fiber, e-fiber, c-fiber, g-fiber, and h-fiber. In addition, for all the samples, the intensities of the rolling textures were higher than those of the shear textures. Moreover, there was a progressive increase in the fraction of high-angle grain boundaries with the increasing strain. Finally, with increasing number of ARB cycles, the intensities of rolling and shear textures changed, and no stable texture was formed.

Enhanced Mechanical Properties and Microstructure of Accumulative Roll-Bonded Co/Pb Nanocomposite

“…This can be ascribed to the reduction in the secondary phase distribution during ARB passes. This behavior was reported by other researchers as well [ 14 , 17 ]. Additionally, it should be mentioned that, in these metal matrix composites, the softer metal (lead) was the matrix and the harder metals (Co and Ag) were the reinforcement.…”

“…However, specimens with a Co content greater than 0.5 wt.% showed lower tensile strength (see Figure 2 a). This can be ascribed to the aggregation of Co particles between ARB-initiated layers, which was accompanied by lowered bond strength [ 14 ]. Therefore, the improved tensile properties in ARB-processed Co/Pb composites were optimized to be at 0.5 wt.% Co.…”

“…As can be seen, finer particles (less than 1 μm) as well as more homogeneous distribution (less than 2 µ apart) were achieved in the Pb–0.5%Co–10pass in comparison to the Pb–0.5%Ag–10pass sample (generally, more than 1.5 μm phase size with particles more than 3 μm apart). This can be ascribed to the lower ductility of cobalt in comparison to Ag, leading to the enhanced work hardening and faster breaking down of Co particles [ 14 ]. In both samples, the continuity of the interfaces between the secondary phase and the matrix was desired without any gap as a consequence of super ductility and lubrication characteristics of the Pb matrix.…”

“…The specifications of the prepared sample are outlined in Table 2. Tensile test specimens were manufactured using a wire cutting instrument on rolled strips that were oriented along the rolling direction, according to the ASTM E8M standard [14]. A Hounsfield H50KS testing machine at a speed of 10 mm/min was used for the tensile tests.…”