摘要
剪挤(SE)成形方法作为一种剧烈塑性变形方法被提出来用于成形薄壁管件,为评估该方法的细晶能力和强化效果,以纯铜管件为研究对象,对其进行4道次的SE成形。金相观察发现剪挤成形的组织得到很好的细化,同时伴随晶粒取向的增大现象。TEM研究表明,纯铜SE细化主要是由剪应变引起的位错细化机制为主,以应变局部化动态再结晶为辅的复合细化机制。此外,成形后材料的HV硬度1070 MPa较成形前材料的硬度400 MPa有很大的提高,该变化主要是位错强化引起的。
A severe plastic deformation method entitled shear extrusion（SE） was proposed to form thin-walled tubular components. This process was validated by experiments in which a pure copper tube was used as investigation object. The effect of SE on grain refinement and strength improvement was assessed. The results of optical microscope observation show a significant grain refinement as well as the increased grain misorientations for the samples processed by four passes of SE. The TEM analysis shows that the dislocation refinement of shear strain is the main reason during the SE process, followed by strain localization leading to dynamic recrystallization. The hardness of undeformed copper cube sample is ~400 MPa, while that of as extruded sample is up to ~1070 MPa. The increase of the hardness is mainly caused by the dislocation generation.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第10期2391-2395,共5页
Rare Metal Materials and Engineering
基金
Aeronautical Science Foundation of China(2011ZE53059)
National Natural Science Foundation of China(51275414)
The Qualified Personnel Foundation of Taiyuan University of Technology(tyut-re201441a)
关键词
剧烈塑性变形
超细晶
铜
挤压
微观组织
severe plastic deformation
ultrafine grain
copper
extrusion
microstructure
