Research on the Microstructure and Mechanical Properties of 6082 Aluminum Alloy FSW Joints based on Welding Speed

LIN Sen; DANG Jian; HAN Xiaohui; LI Gangqing; ZHANG Tiehao; ZHAO Cunjin

doi:10.7512/j.issn.1001-2303.2024.09.04

High-performance Welding Manufacturing of Rail Vehicles | Views : 0 下载量: 796 CSCD: 0

PDF
Export
Share
Collection
Album

Research on the Microstructure and Mechanical Properties of 6082 Aluminum Alloy FSW Joints based on Welding Speed
Vol. 54, Issue 9, Pages: 30-37(2024)
Received：20 August 2024，

Published：25 September 2024
DOI： 10.7512/j.issn.1001-2303.2024.09.04
稿件说明：

移动端阅览

林森，党键，韩晓辉，等.基于焊接速度的6082铝合金FSW接头组织与力学性能调控研究［J］.电焊机，2024，54（9）：30-37. DOI： 10.7512/j.issn.1001-2303.2024.09.04.

LIN Sen, DANG Jian, HAN Xiaohui, et al.Research on the Microstructure and Mechanical Properties of 6082 Aluminum Alloy FSW Joints based on Welding Speed[J].Electric Welding Machine, 2024, 54(9): 30-37. DOI： 10.7512/j.issn.1001-2303.2024.09.04.

摘要

为研究焊接速度对6082铝合金搅拌摩擦焊（FSW）接头微观组织和力学性能的影响，并建立基于焊接速度的FSW接头组织与性能调控规律。通过金相观察、电子背散射衍射（EBSD）分析、硬度测试、室温拉伸和弯曲试验等手段，对四种不同焊接速度（500 mm/min、750 mm/min、1 000 mm/min、1 250 mm/min）下FSW接头的微观组织和力学性能进行表征。结果表明，随着焊接速度的增大，FSW接头的微观组织发生显著变化。焊核区（NZ）发生连续动态再结晶，形成细小的再结晶晶粒组织，其平均晶粒尺寸从3.8 μm减小至2.3 μm，再结晶分数从83%减小至57.3%；热机影响区（TMAZ）发生部分动态回复和部分动态再结晶，晶界处出现少量细小等轴晶粒，晶内形成大量亚晶组织。亚结构比例和小角度晶界比例显著增加，分别为69.2%和60.1%；受焊接热影响，热影响区（HAZ）相比母材区（BM）的晶粒尺寸略有增大，再结晶程度和晶界角度分布与母材相似。力学性能方面，随着焊接速度增大，FSW接头硬度最低值从72.3 HV增大至81.2 HV，焊接系数从74.7%提升至89.0%，热影响软化区明显缩小，但在1 250 mm/min焊速下FSW接头背弯试样产生裂纹。基于焊接速度的调控模式，1 000 mm/min焊接速度下FSW接头具有最优的力学性能。

Abstract

The purpose of this study is to investigate the effects of welding speed on the microstructure and mechanical properties of 6082 aluminum alloy friction stir welding (FSW) joints

and to establish the regulation rules of FSW joint microstructure and properties based on welding speed. Metallographic observation

electron backscatter diffraction (EBSD) analysis

hardness testing

room temperature tensile and bending tests were used to characterize the microstructure and mechanical properties of FSW joints at four different welding speeds (500 mm/min

750 mm/min

1000 mm/min

1 250 mm/min). The results show that with the increase of welding speed

the microstructure of FSW joints changes significantly. In the weld nugget zone (NZ)

continuous dynamic recrystallization occurs

forming fine recrystallized grain structures

with the average grain size decreasing from 3.8 μm to 2.3 μm and the recrystallization fraction decreasing from 83% to 57.3%; In the thermomechanically affected zone (TMAZ)

partial dynamic recovery and partial dynamic recrystallization occur

with a few fine equiaxed grains appearing at the grain boundaries and a large number of subgrain structures forming inside the grains. The proportion of substructure and the proportion of small-angle grain boundaries increase significantly

reaching 69.2% and 60.1% respectively; Due to the welding heat effect

the grain size in the heat-affected zone (HAZ) increases slightly compared to the base metal zone (BM)

and the degree of recrystallization and grain boundary angle distribution are similar to those of the base metal. In terms of mechanical properties

with the increase of welding speed

the minimum hardness of FSW joints increases from 72.3 HV to 81.2 HV

the welding coefficient increases from 74.7% to 89%

and the heat-affected softening zone is significantly reduced. However

cracks occur in the back-bend specimen of FSW joints at a welding speed of 1 250 mm/min. Based on the welding speed control mode

the FSW joint has the best mechanical properties at a welding speed of 1 000 mm/min.

关键词

Keywords

references

Mishra R S ， Ma Z Y . Friction stir welding and processing ［J］. Materials science and engineering：R：reports ， 2005 ， 50 （ 1-2 ）： 1 - 78 .

张欣盟，何广忠，王贝贝，等 . 6082-T6铝合金填料搅拌摩擦焊工艺［J］. 电焊机， 2020 ， 50 （ 12 ）： 54 - 58 .

ZHANG X M ， HE G Z ， WANG B B ， et al . Investigation of friction stir welded 6082-T6 Al alloy with fillers ［J］. Electric Welding Machine ， 2020 ， 50 （ 12 ）： 54 - 58 .

Lin S ， Deng Y L ， Lin H Q ， et al . Microstructure， mechanical properties and stress corrosion behavior of friction stir welded joint of Al-Mg-Si alloy extrusion ［J］. Rare Metals ， 2018 ： 1 - 11 .

Ogunsemi B T ， Abioye T E ， Ogedengbe T I ， et al . A review of various improvement strategies for joint quality of AA 6061-T6 friction stir weldments . Journal of Materials Research and Technology ， 2021 ， 11 ： 1061 - 1089 .

赵刚，蔡乃星，刘旭升，等 . 中厚板2219铝合金双轴肩搅拌摩擦焊焊接残余应力及微观组织演变［J］. 电焊机， 2023 ， 53 （ 03 ）： 111 - 116 .

ZHAO G ， CAI N X ， LIU X S ， et al . Residual Stress and Microstructure Evolution of Bobbin Tool Friction Stir Welded 2219 Aluminum Alloy Thick Plates ［J］. Electric Welding Machine ， 2023 ， 53 （ 03 ）： 111 - 116 .

Den B A J ， Werkhoven R J ， Sillekens W H ， et al . The origin of weld seam defects related to metal flow in the hot extrusion of aluminum alloys EN AW-6060 and EN AW-6082 ［J］. Journal of Materials Processing Tech. ， 2014 ， 214 （ 11 ）： 2349 - 2358 .

Wu L J ， Yang B ， Han X H ， et al . The microstructure and mechanical properties of 5083，6005A and 7N01 alumi num alloy gas metal arc-welded joints for high-speed train：a comparative study ［J］. Metals ， 2022 ， 12 （ 2 ）： 213 .

马寅，张志毅，韩晓辉，等 . 修复次数对6082铝合金焊接接头残余应力的影响［J］. 中国有色金属学报， 2023 ， 33 （ 10 ）： 3185 - 3194 .

MA Y ， ZHANG Z Y ， HAN X H ， et al . Influence of repair welding times on residual stresses of 6082 aluminum alloy welded joint ［J］. The Chinese Journal of Nonferrous Metals ， 2023 ， 33 （ 10 ）： 3185 - 3194 .

刘胜胆，陈小连，张端正，等 . 固溶温度对6082铝合金显微组织与性能的影响［J］. 中国有色金属学报， 2015 ， 25 （ 3 ）： 582 - 588 .

LIU S D ， CHEN X L ， ZHANG D Z ， et al . Effect of solution heat treatment temperature on microstructure and properties of 6082 aluminum alloy ［J］. The Chinese Journal of Nonferrous Metals ， 2015 ， 25 （ 3 ）： 582 - 588 .

张国鹏 . 热处理工艺对新型6XXX系铝合金组织与性能的影响［D］. 湖南：中南大学， 2011 .

ZHANG G P . The influence of heat treatment process on the microstructure and properties of a new 6XXX series aluminum alloy ［D］. Hunan ： Central South University ， 2011 .

马闻宇 . AA6082铝合金热冲压成形控性规律研究及工艺优化［D］. 北京：北京科技大学， 2016 .

MA W Y . Research on law of formability and property for hot stamping AA6082 aluminum alloy and process optimisation ［D］. Beijing ： University of Science and Technology Beijing ， 2016 .

Misra R S ， De P S ， Kumar N . Friction stir welding and processing： science and engineering ［M］. New York ： Springer Ltd ， 2014 .

邹阳帆，李文亚，褚强，等 . 焊接速度对BT-FSW 2219铝合金接头流动行为及组织与力学性能影响分析［J］. 焊接学报， 2022 ， 43 （ 11 ）： 56-62+165 - 166 .

ZOU Y F ， LI W Y ， ZHU Q ， et al . Effect of welding speed on material flow， microstructure and mechanical properties of BT-FSW 2219 aluminum alloy joints ［J］. Transactions of the China Welding Institution ， 2022 ， 43 （ 11 ）： 56-62+165 - 166 .

Mcnelley T R ， Swaminathan S ， Su J Q . Recrystallization mechanisms during friction stir welding/processing of aluminum alloys ［J］. Scripta Materialia ， 2008 ， 58 （ 5 ）： 349 - 354 .

Sidhar H ， Martinez N Y ， Mishra R S ， et al . Friction stir welding of Al-Mg-Li 1424 alloy ［J］. Materials & Design ， 2016 ， 106 ： 146 - 152 .