铝合金深冷挤压切削加工有限元仿真及实验研究  

Finite Element Simulation and Experimental Research on Aluminum Alloy Processed by Cryogenic Temperature Extrusion Machining

作　　者：殷晓龙 吴亚威 王志林 郭润宇 王婉 马少彬 张素香[1] 徐景霞 YIN Xiaolong;WU Yawei;WANG Zhilin;GUO Runyu;WANG Wan;MA Shaobin;ZHANG Suxiang;XU Jingxia(School of Mechatronics Engineering,Zhongyuan University of Technology,Zhengzhou 450007,China)

机构地区：[1]中原工学院机电学院,郑州450007

出　　处：《精密成形工程》2024年第8期130-137,共8页Journal of Netshape Forming Engineering

基　　金：国家自然科学基金(52105499);中原工学院学科青年硕导培育计划(SD202406);中原工学院基本科研业务费专项资金项目(K2022YY001);中原工学院青年骨干教师资助项目(2024XQG09)。

摘　　要：目的为提升大变形技术的加工效率和质量,消除变形热带来的影响,提出一种基于传统切削的深冷挤压切削(Cryogenic Temperature Extrusion Machining,CT-EM)工艺,并通过数值模拟与实验验证了该方法的可靠性。方法利用DEFORM软件中的点追踪与流动网格法对不同切削压缩比(1.4、1.6、1.8)条件下的等效应变、应变率及切屑成形过程进行了有限元模拟,开展了切削实验,并对切屑的形貌及微观组织进行了分析。结果挤压切削分为初始切入、切屑成形以及稳定成形3个阶段,第二变形区的网格畸变最严重;等效应变随着压缩比的增大而增大,其值在1.2~1.6之间,与计算值较吻合;等效应变率产生于第一变形区宽度为200~250μm的区域,且CT-EM具有更高的等效应变率;CT-EM制备的切屑带材表面粗糙度低、裂纹少、成形能力更优,切屑内的微观组织被强烈细化(<200 nm),达到了超细晶结构,且产生了大量的位错缠结区。结论深冷处理可提升7系铝合金切削加工时的成形能力,晶粒细化是较大的等效应变与应变率共同作用的结果,模拟数据对实验结果有较好的支撑。The work aims to propose a novel cryogenic temperature extrusion machining(CT-EM)process based on tradi-tional cutting,in order to improve the processing efficiency and quality of severe plastic deformation technologies and eliminate the effect of deformation heat and verify the reliability of this method through numerical simulation and experiments.Finite element simulation was conducted on the equivalent strain,strain rate,and chip forming process under different cutting com-pression ratios(1.4,1.6,1.8)by point tracking and flow grid method in DEFORM software.Cutting experiments were con-ducted,and morphology and microstructure of the chips were analyzed.The extrusion machining process could be divided into three stages of initial cutting,chip formation and stable forming.The grid distortion in the second deformation zone was the most severe.The equivalent strain increased with the increase of compression ratio,with a value between 1.2 and 1.6,which was in good agreement with the calculated value.The equivalent strain rate occurred in the first deformation zone with a width of 200-250μm.The CT-EM process had a higher equivalent strain rate.The surface roughness of the chip strip prepared by CT-EM was low,with fewer cracks and better formability.The microstructure inside the chip was strongly refined(<200 nm),achieving ultrafine grain structure and generating a large number of dislocation entanglement areas.Cryogenic treatment can improve the formability of 7 series aluminum alloys during machining,and grain refinement is the result of the combined effect of large equivalent strain and strain rate.Simulation data provides good support for the experimental results.

关 键 词：深冷挤压切削 有限元模拟 等效应变 应变率 成形能力 微观组织 

分 类 号：TG51.1[金属学及工艺—金属切削加工及机床]