Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys
The material flow behavior during friction stir welding (FSW) plays a critical role in the quality of final joints. In this study, the FSW of LAZ931 duplex Mg alloy was carried out at a rotation speed of 800 rpm and welding speeds of 50, 100, and 200 mm/min, respectively. A thin pure Mg strip insert...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
|
| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/14/11/1305 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850266577828577280 |
|---|---|
| author | Shiquan Cui Wenguan Cao Qi Zhang Liguo Wang Yufeng Sun Shaokang Guan |
| author_facet | Shiquan Cui Wenguan Cao Qi Zhang Liguo Wang Yufeng Sun Shaokang Guan |
| author_sort | Shiquan Cui |
| collection | DOAJ |
| description | The material flow behavior during friction stir welding (FSW) plays a critical role in the quality of final joints. In this study, the FSW of LAZ931 duplex Mg alloy was carried out at a rotation speed of 800 rpm and welding speeds of 50, 100, and 200 mm/min, respectively. A thin pure Mg strip inserted at the interface between the two Mg-Li alloy plates was used as a marker to study the flow behavior of the materials in the FSW process. Sound welds with no defects were obtained for all three welding speeds. The microstructural evaluations along the marker on the horizontal cross-section around the keyhole of the welds were characterized. As the welding speed increased, the marker came closer to the keyhole, indicating the decreased extent of the plastic deformation of the material. In the shoulder-affected zone (SAZ), the thickness of the marker reduced gradually in the accelerating stage and finally accumulated together in the decelerating stage. However, in the pin-affected zone (PAZ), the thickness of the marker reduced sharply in the accelerating stage and then became dispersed in the decelerating stage, and the degree of dispersion decreased as the weld speed increased. As a result, an elongated grain structure was formed in the SAZ, while two equiaxial grain structures were formed in the PAZ. The material on the advancing side was refined by the pin and deposited in the weld to form a fine equiaxial grain structure due to the high strain rate. In contrast, the material on the retreating side was pushed by the pin and thus directly deposited in the weld to form a coarse equiaxial grain structure. In addition, the area of the fine equiaxial grain structure was reduced obviously with the increase in welding speed. |
| format | Article |
| id | doaj-art-e13ccad71dfb4a2e89570e50c3bc9323 |
| institution | OA Journals |
| issn | 2075-4701 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj-art-e13ccad71dfb4a2e89570e50c3bc93232025-08-20T01:54:07ZengMDPI AGMetals2075-47012024-11-011411130510.3390/met14111305Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li AlloysShiquan Cui0Wenguan Cao1Qi Zhang2Liguo Wang3Yufeng Sun4Shaokang Guan5School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, ChinaThe material flow behavior during friction stir welding (FSW) plays a critical role in the quality of final joints. In this study, the FSW of LAZ931 duplex Mg alloy was carried out at a rotation speed of 800 rpm and welding speeds of 50, 100, and 200 mm/min, respectively. A thin pure Mg strip inserted at the interface between the two Mg-Li alloy plates was used as a marker to study the flow behavior of the materials in the FSW process. Sound welds with no defects were obtained for all three welding speeds. The microstructural evaluations along the marker on the horizontal cross-section around the keyhole of the welds were characterized. As the welding speed increased, the marker came closer to the keyhole, indicating the decreased extent of the plastic deformation of the material. In the shoulder-affected zone (SAZ), the thickness of the marker reduced gradually in the accelerating stage and finally accumulated together in the decelerating stage. However, in the pin-affected zone (PAZ), the thickness of the marker reduced sharply in the accelerating stage and then became dispersed in the decelerating stage, and the degree of dispersion decreased as the weld speed increased. As a result, an elongated grain structure was formed in the SAZ, while two equiaxial grain structures were formed in the PAZ. The material on the advancing side was refined by the pin and deposited in the weld to form a fine equiaxial grain structure due to the high strain rate. In contrast, the material on the retreating side was pushed by the pin and thus directly deposited in the weld to form a coarse equiaxial grain structure. In addition, the area of the fine equiaxial grain structure was reduced obviously with the increase in welding speed.https://www.mdpi.com/2075-4701/14/11/1305friction stir weldingmaterial flowMg-Li alloymicrostructure |
| spellingShingle | Shiquan Cui Wenguan Cao Qi Zhang Liguo Wang Yufeng Sun Shaokang Guan Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys Metals friction stir welding material flow Mg-Li alloy microstructure |
| title | Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys |
| title_full | Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys |
| title_fullStr | Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys |
| title_full_unstemmed | Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys |
| title_short | Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys |
| title_sort | material flow and microstructural evolution in friction stir welding of laz931 duplex mg li alloys |
| topic | friction stir welding material flow Mg-Li alloy microstructure |
| url | https://www.mdpi.com/2075-4701/14/11/1305 |
| work_keys_str_mv | AT shiquancui materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys AT wenguancao materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys AT qizhang materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys AT liguowang materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys AT yufengsun materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys AT shaokangguan materialflowandmicrostructuralevolutioninfrictionstirweldingoflaz931duplexmglialloys |