摘要
将连续挤压与等通道模具相结合,通过有限元模拟、金相显微镜、X射线衍射仪和透射电子显微镜分析大应变条件下铝锶中间合金微观组织的变化机制。结果表明:等通道模具中等效应变最大值可达16,出现在经过第一转角外角的a路径上,对Al_(4)Sr相细化效果最好,各路径对Al_(4)Sr相的细化作用为:内侧a路径>中间b路径>外侧c路径;采用这种一模双孔的挤压方式,可以使进料口中心粗大的Al_(4)Sr相粒子经过等通道模具中应变最大的a路径,使其得到有效细化,最终使得产品中心和边缘的Al_(4)Sr相均得到有效细化,尺寸约为4.5μm。透射电镜观察表明,经过大塑性变形后,由于累积应变值增加,微观应变增大,Al_(4)Sr相内部位错缠结交割,形成位错墙,与外部位错相互作用,使Al_(4)Sr相粒子断裂碎化,对Al_(4)Sr相粒子产生了显著的细化效果,同时由于界面能的增大,促使Al_(4)Sr相出现少量回溶。
The continuous extrusion is combined with an equal-channel die.The microstructure evolution of Al-Sr master alloy under large strain extrusion was analyzed by finite-element simulation,OM,XRD,and TEM.The results show that the maximum effective strain in the equal-channel die reaches 16,which appears on the a-path passing through the outer corner of the first die angle,and the refinement effect of Al_(4)Sr phase is the best.The refinement effect of each path on Al_(4)Sr phase is as follows:inner a-path>middle b-path>outside c-path.Using the extrusion method with one die of double hole,the coarse Al_(4)Sr phase particles in the center of cavity inlet can pass through the a-path with the largest strain in the equal-channel die,so that they can be effectively refined.Finally the particles of Al_(4)Sr phase in the center and edge of the product are effectively refined,with an average length of about 4.5μm.Transmission electron microscopy observation shows that after large plastic deformation,due to the increased cumulative strain and increased microscopic strain,the internal dislocations of Al_(4)Sr phase are entangled and delivered,forming a dislocation wall that interacts with the external dislocations to break Al_(4)Sr phase particles.The fragmentation exerts a significant refining effect on Al_(4)Sr phase particles.At the same time,due to the increased interfacial energy,a small amount of Al_(4)Sr phase dissolves.
作者
赵颖
王俊霖
运新兵
郭丽丽
闫志勇
张旭
Zhao Ying;Wang Junlin;Yun Xinbing;Guo Lili;Yan Zhiyong;Zhang Xu(Engineering Research Center of Continuous Extrusion of Ministry of Education,Dalian Jiaotong University,Dalian 116028,China;Dalian Konform Technology Co.,Ltd,Dalian 116028,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2023年第3期1094-1102,共9页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51705062)
辽宁省科技攻关计划(2021JH1/10400080)。
关键词
铝锶中间合金
连续挤压
等通道变形
组织演变
Al-Sr master alloy
continuous extrusion
equal channel deformation
microstructure evolution
作者简介
赵颖,女,1980年生,博士,副教授,大连交通大学连续挤压教育部工程研究中心,辽宁大连116028,E-mail:zhaoying@djtu.edu.cn。
