摘要
挤出切削是一种新型剧烈塑性变形工艺,通过设计特定的材料塑性流动通道,使得材料在切削和挤出的共同作用下,实现一步法制备具有梯度结构的超细晶金属板材或带材,具有工艺简单、所需装备成熟、制造效率高等优点。目前关于挤出切削成形工艺、机理以及制备的梯度超细晶结构材料性能方面研究非常匮乏。通过理论分析、试验以及数值分析相结合的方法,对不同挤出厚度下梯度结构铝带材1060的成形过程进行探究,分析挤出切削加工机理以及工艺参数对制备梯度结构铝带材1060的影响规律。研究结果表明,随着挤出厚度的增加,高应变区范围无明显变化,但低应变区增大,更多的材料从侧向挤出。挤出切削制备的梯度结构铝带材晶粒细化显著,硬度提升明显,晶粒尺寸与硬度在厚度层上均呈明显的梯度分布规律。制备的梯度结构铝带材的拉伸强度随着挤出厚度的增加呈下降趋势,而延伸率有所上升。相比原始样品,梯度结构铝带材的拉伸强度几乎提升了一倍,而延伸率仅略微下降。研究表明,挤出切削是一种可行且高效的梯度结构材料制备工艺,可通过调控工艺参数制备不同梯度分布的材料。
Extrusion-Machining is a kind of novel severe plastic deformation process. Through the design of specific material plastic flow channel, the ultrafine-grained metal sheets or strips with gradient structure can be prepared by the one-step method under the combined action of machining and extrusion. It has the obvious advantages of simple process, mature equipments and high manufacturing efficiency. Currently, there is very few research on the forming process, mechanism of Extrusion-Machining and the performance of gradient ultrafine-grained microstructure materials prepared by it. Through a combination of theoretical, experimental and numerical analysis, the forming process of gradient structural aluminum strip 1060 under different extrusion thicknesses is investigated. The influence of the machining mechanism and process parameters of Extrusion-Machining on the preparation of samples is analyzed. The results show that with the increase of the extrusion thickness, no significant change in the range of high-strain areas, but the low-strain zone is more widely distributed, and more material is extruded laterally. The gradient structural aluminum strip has significant grain refinement and hardness enhancement, which both show obvious gradient distribution in the thickness layer. The tensile strength of gradient sample decreases with the increase of extrusion thickness, while the elongation increases. The tensile strength of the gradient structural aluminum strip is almost twice higher than that of the original sample, while the elongation only decreases slightly. This study implies that Extrusion-Machining is a feasible and efficient process for preparing gradient structure materials, which can be used for preparing materials with different gradient distributions by adjusting the process parameters.
作者
邓文君
曾俞宁
周子涵
DENG Wen-jun;ZENG Yu-ning;ZHOU Zi-han(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510640)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第5期278-288,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金(52075187,51375174)
广东省自然科学基金(s2013050014163,2214050007269)资助项目。
关键词
挤出切削
梯度结构铝带材
梯度超细晶结构
extrusion-machining
gradient structural aluminum strip
gradient ultrafine-grained microstructure
