Lee Seong-Hee, Kim Hyoung-Wook, Lim Cha-Yong
Department of Advanced Materials Science and Engineering, Mokpo National University, Muan-gun 534-729, Chonnam, Korea.
J Nanosci Nanotechnol. 2011 Feb;11(2):1613-6. doi: 10.1166/jnn.2011.3350.
A nanostructured deoxidized low-phosphorous copper (DLPC) was fabricated by three-layer stack accumulative roll-bonding (ARB) process. The microstructural evolution and the variation of mechanical properties with three-layer stack ARB were investigated in detail. It was found that the microstructure has been evolved from a dislocation cell structure to ultrafine grained structure as the number of ARB cycles increases. In addition, the mean spacing of grain boundaries, which was 45 microm in initial material, reduced to 2.1 microm after 1 cycle, 360 nm after 3 cycles, 250 nm after 5 cycles, then 170 nm after 7 cycles, progressively. The fraction of high-angle grain boundaries after 1-cycle ARB was no more than 0.27, but it increased with the number of ARB cycles, and became surprisingly more than 0.7 after 7-cycle ARB. The tensile strength increased with the number of ARB cycles, and then after 7 cycles it reached about 600 MPa, which is about 2.5 times higher than that of the initial material. Therefore, the three-layer stack ARB is very effective for development of ultrafine grains and high strengthening of DLPC alloy.
通过三层堆叠累积轧制粘结（ARB）工艺制备了一种纳米结构的低磷脱氧铜（DLPC）。详细研究了三层堆叠ARB过程中的微观结构演变和力学性能变化。结果发现，随着ARB循环次数的增加，微观结构从位错胞结构演变为超细晶粒结构。此外，初始材料中晶界的平均间距为45微米，经过1次循环后减小到2.1微米，3次循环后为360纳米，5次循环后为250纳米，7次循环后为170纳米，呈逐渐减小趋势。1次循环ARB后高角度晶界的比例不超过0.27，但随着ARB循环次数的增加而增加，7次循环ARB后惊人地超过了0.7。抗拉强度随着ARB循环次数的增加而提高，7次循环后达到约600兆帕，约为初始材料的2.5倍。因此，三层堆叠ARB对于DLPC合金的超细晶粒发展和高强度强化非常有效。
