超延展变形行为与塑性提高机制
(北京科技大学 材料先进制备技术教育部重点实验室，北京 100083)
摘 要: 以本文作者所在课题组近年来的工作为基础，介绍了高性能连续柱状晶组织纯铜的室温超延展性、热交换用连续柱状晶组织BFe10−1−1管材的高塑性以及高弹高导Cu-12%Al(质量分数)合金的室温塑性提升。研究发现，连续柱状晶组织的高取向性、平直的低能小角晶界以及在强塑性变形过程中高组分的 “软”取向织构及不同于普通多晶组织的动态回复、组织演化特征，是其塑性提升、具有超延展变形能力的主要原因，总结了连续柱状晶组织塑性提高与超延展变形性的相关机制。研究结果为改善材料尤其是脆性材料和难加工材料的室温塑性与可加工性能提供了理论依据和新思路。
关键字: 连续柱状晶组织；室温超延展性；塑性提升；变形机制；织构；晶界；组织演化
mechanisms of continuous columnar-grained copper and copper alloys
（Key Laboratory for Advanced Materials Processing, Ministry of Education,
University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The major research advances are recommended that the extreme plastic extensibility of the high performance continuous columnar-grained (CCG) copper as well as the ductility improvement both of the CCG BFe10−1−1 alloy tube for heat exchanger and the CCG Cu-12%Al (mass fraction) alloy with high elasticity and high electrical conductivity, based on the work of the author’s research team over recent years. It is concluded that the highly-textured columnar grains along the solidification direction (SD), the straight small-angle grain boundaries with low boundary energy, the high fraction of “soft-oriented” drawn texture component, the dynamic recovery mechanisms and microstructure evolution of the continuous columnar grains during the extreme plastic deformation, which are significantly different from the behaviors of the ordinary polycrystal, account for the enhanced ductility and extreme plastic extensibility of the CCG copper and copper alloys. The relative mechanisms of the extreme plastic extensibility and ductility improvement for CCG copper and copper alloys are summarized so as to provide theoretical basis and new method for the modification of the ductility and workability of materials, especially for those brittle and hard-to-work materials.
Key words: continuous columnar grains; extreme plastic extensibility; ductility improvement; deformation mechanism; texture; grain boundary; microstructure evolution
