(1. 东北大学 材料与冶金学院, 沈阳 110006;
2. 东北大学 测试中心, 沈阳 110006)
摘 要: 探讨一种连续等通道角挤压（ECAP）新技术, 实现了纯铝的无限长度连续大变形, 制备出具有超细晶结构的金属材料。 组织和性能检测表明：在连续ECAP变形一道次后, 在晶粒内部形成了直径为650~900 nm且内部基本无位错的亚晶, 但部分大晶粒内部仍存在高密度的位错网, 材料硬度提高了87%； 经过4道次连续ECAP变形后, 亚晶并未进一步细化, 但亚晶界趋于平直、清晰, 且亚晶内部基本未见位错组织, 材料硬度提高也不显著； 与传统ECAP相比, 连续ECAP工艺由于具有较高的变形区温度, 促进了晶内位错的反应即动态回复过程, 较早形成了平直清晰的亚晶结构, 同时伴随每道次变形过程的动态回复也降低了最后晶格中累积的能量, 使变形两道次后的组织和性能变化不显著。
关键字: 铅； 超细晶； 晶界； 亚晶； 连续等通道角挤压
（1. School of Materials and Metallurgy, Northeastern University,
Shenyang 110006, China;
2. Test center, Northeastern University, Shenyang 110006, China）
Abstract: A new continuous equal channel angular pressing (ECAP) technique was developed and successfully produced unlimited length of pure aluminum with ultrafine grain. After one ECAP deformation pass, profuse subgrains with the size of 650-900 nm are formed, few dislocations can be found inside the subgrains, but high density dislocation networks still are observed in some grains, the hardness of material increases 87%. After four ECAP deformation passes, the sizes of subgrains change little, but the subgrain boundary becomes straight and thinner, the increment of hardness is insignificant. Compared with the traditional ECAP technology, much higher temperature in deformed zone during the continuous ECAP deformation accelerate the process of dynamic recovery, so many clear subgrains form even after one ECAP deformation pass, the microstructures and hardness change little with the increase of ECAP deformation passes.
Key words: aluminium; ultrafine grain; grain boundary; subgrain; continuous equal channel angular pressing
