超延展變形行為與塑性提高機制
(北京科技大學(xué) 材料先進制備技術(shù)教育部重點實驗室，北京 100083)
摘 要: 以本文作者所在課題組近年來的工作為基礎(chǔ)，介紹了高性能連續(xù)柱狀晶組織純銅的室溫超延展性、熱交換用連續(xù)柱狀晶組織BFe10−1−1管材的高塑性以及高彈高導(dǎo)Cu-12%Al(質(zhì)量分數(shù))合金的室溫塑性提升。研究發(fā)現(xiàn)，連續(xù)柱狀晶組織的高取向性、平直的低能小角晶界以及在強塑性變形過程中高組分的 “軟”取向織構(gòu)及不同于普通多晶組織的動態(tài)回復(fù)、組織演化特征，是其塑性提升、具有超延展變形能力的主要原因，總結(jié)了連續(xù)柱狀晶組織塑性提高與超延展變形性的相關(guān)機制。研究結(jié)果為改善材料尤其是脆性材料和難加工材料的室溫塑性與可加工性能提供了理論依據(jù)和新思路。
關(guān)鍵字: 連續(xù)柱狀晶組織；室溫超延展性；塑性提升；變形機制；織構(gòu)；晶界；組織演化
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
