Low Temperature Recrystallization of High Purity Iron Severely Deformed by ARB Process
Low Temperature Recrystallization of High Purity Iron Severely Deformed by ARB Process
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ARB工艺严重变形高纯铁的低温再结晶
DOI：
10.4028/www.scientific.net/msf.558-559.357
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
N. Tsuji
中科院分区：
文献类型：
--
作者：
D. Terada;B. Li;M. Sugiyama;N. Tsuji
研究了SPD处理的高纯铁的再结晶行为。 99.95% 的铁片在环境温度下通过累积轧制 (ARB) 工艺变形达 8 个周期（等效应变为 6.4）。随后，经过 ARB 处理的样品在 300°C 至 500°C 的不同温度下退火 1.8ks。通过 TEM 和 SEM/EBSP 对这些样品的微观结构进行了表征。 as-ARB处理样品的微观结构显示出沿RD方向拉长的层状边界结构，这是ARB处理材料的典型微观结构。层状边界的平均间隔为约100nm。经过400℃退火后，ARB试样呈现出由晶粒尺寸大于10 5 m的等轴晶组成的部分再结晶显微组织和恢复的层状晶界结构。经过500℃以上退火后，显微组织中充满等轴再结晶晶粒。这些结果表明，以成核和生长为特征的传统不连续再结晶在400℃以上的退火温度下发生。在之前的工作中报道了低碳IF钢ARB加工的退火行为，在退火温度高于600℃的退火过程中发生了连续再结晶。纯铁的再结晶温度远低于IF钢，且再结晶过程也有显着差异。这种差异被认为是由 ARB 加工的纯铁微观结构不均匀造成的。
Recrystallization behavior of SPD processed high purity iron was studied. The 99.95% iron sheet was deformed by the accumulative roll-bonding (ARB) process up to 8 cycles (equivalent strain of 6.4) at ambient temperature. Subsequently, the ARB-processed specimens were annealed for 1.8ks at various temperatures from 300°C to 500°C. The microstructures of these specimens were characterized by TEM and SEM/EBSP. The microstructure of the as-ARB-processed specimens showed the lamellar boundary structure elongated along RD, which was the typical microstructure of the ARB-processed materials. The mean interval of the lamellar boundaries was about 100 nm. After annealing at 400°C, the ARB specimen showed a partially recrystallized microstructure composed of equiaxed grains with grain size larger than 10 5m and the recovered lamellar boundary structure. After annealing above 500°C, the microstructures were filled with equiaxed recrystallized grains. These results suggest that conventional discontinuous recrystallization characterized by nucleation and growth occurs during annealing at annealing temperature above 400 °C. In previous work reported about the annealing behavior of the low carbon IF steel ARB processed, the continuous recrystallization occurred during annealing at annealing temperature above 600 °C. The recrystallization temperature of the pure iron was much lower than the IF steel and the recrystallization process were significantly different. This difference was suggested to be caused by inhomogeneous microstructure in the pure iron ARB-processed.