Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints
The corrosion fatigue properties and fracture characteristics of friction stir welding joints of 7075 aluminum alloys were studied via corrosion fatigue tests, electrochemical measurements, and corrosion fatigue morphology and microstructure observations. The results show that the corrosion fatigue...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2020-09-01
|
Series: | Materials |
Subjects: | |
Online Access: | https://www.mdpi.com/1996-1944/13/18/4196 |
id |
doaj-270ab860b960429da19ff46a71057c97 |
---|---|
record_format |
Article |
spelling |
doaj-270ab860b960429da19ff46a71057c972020-11-25T03:23:24ZengMDPI AGMaterials1996-19442020-09-01134196419610.3390/ma13184196Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy JointsQingna Ma0Fei Shao1Linyue Bai2Qian Xu3Xingkun Xie4Mei Shen5College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaCollege of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaCollege of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaCollege of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaCollege of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaCollege of Field Engineering, Army Engineering University of PLA, Nanjing 210007, ChinaThe corrosion fatigue properties and fracture characteristics of friction stir welding joints of 7075 aluminum alloys were studied via corrosion fatigue tests, electrochemical measurements, and corrosion fatigue morphology and microstructure observations. The results show that the corrosion fatigue crack of the friction stir welding (FSW) joint of 7075 aluminum alloys originated in the junction zone between the thermomechanically affected zone and the weld nugget zone. The corrosion fatigue life of the joint decreased with increasing stress amplitude, with an S–N curve equation of lgN = 5.845 − 0.014S. Multiple crack sources were observed in the corrosion fatigue fracture. The main crack source originated from the corrosion pits at the interface between the thermomechanically affected zone and the weld nugget zone due to the influence of the coarse microstructure and the large potential difference between both zones. Corrosion morphologies of a rock candy block and an ant nest appeared in the crack propagation zone and the grain boundary of the weld nugget zone. In addition, fatigue speckles and intergranular fractures were observed, as well as brittle fracture characterized by cleavage steps and secondary cracks in the final fracture zone.https://www.mdpi.com/1996-1944/13/18/41967075 aluminum alloyFSW jointcorrosion fatiguemicroscopic structurefracture characters |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Qingna Ma Fei Shao Linyue Bai Qian Xu Xingkun Xie Mei Shen |
spellingShingle |
Qingna Ma Fei Shao Linyue Bai Qian Xu Xingkun Xie Mei Shen Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints Materials 7075 aluminum alloy FSW joint corrosion fatigue microscopic structure fracture characters |
author_facet |
Qingna Ma Fei Shao Linyue Bai Qian Xu Xingkun Xie Mei Shen |
author_sort |
Qingna Ma |
title |
Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints |
title_short |
Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints |
title_full |
Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints |
title_fullStr |
Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints |
title_full_unstemmed |
Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints |
title_sort |
corrosion fatigue fracture characteristics of fsw 7075 aluminum alloy joints |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2020-09-01 |
description |
The corrosion fatigue properties and fracture characteristics of friction stir welding joints of 7075 aluminum alloys were studied via corrosion fatigue tests, electrochemical measurements, and corrosion fatigue morphology and microstructure observations. The results show that the corrosion fatigue crack of the friction stir welding (FSW) joint of 7075 aluminum alloys originated in the junction zone between the thermomechanically affected zone and the weld nugget zone. The corrosion fatigue life of the joint decreased with increasing stress amplitude, with an S–N curve equation of lgN = 5.845 − 0.014S. Multiple crack sources were observed in the corrosion fatigue fracture. The main crack source originated from the corrosion pits at the interface between the thermomechanically affected zone and the weld nugget zone due to the influence of the coarse microstructure and the large potential difference between both zones. Corrosion morphologies of a rock candy block and an ant nest appeared in the crack propagation zone and the grain boundary of the weld nugget zone. In addition, fatigue speckles and intergranular fractures were observed, as well as brittle fracture characterized by cleavage steps and secondary cracks in the final fracture zone. |
topic |
7075 aluminum alloy FSW joint corrosion fatigue microscopic structure fracture characters |
url |
https://www.mdpi.com/1996-1944/13/18/4196 |
work_keys_str_mv |
AT qingnama corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints AT feishao corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints AT linyuebai corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints AT qianxu corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints AT xingkunxie corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints AT meishen corrosionfatiguefracturecharacteristicsoffsw7075aluminumalloyjoints |
_version_ |
1724606493583474688 |