Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg
Aluminum alloy is an important material used in railway train structures. It is of great significance to repair aluminum alloy through directional energy deposition to reduce cost and improve the performance of the aluminum alloy. In this study, 7N01 aluminum alloy was repaired by means of laser-dir...
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MDPI AG
2023-04-01
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| author | Jibing Chen Shanji Yu Junsheng Yang Rong Xu Ruidi Li Shisen Huang Hongbin Zhu Xinyan Liu |
| author_facet | Jibing Chen Shanji Yu Junsheng Yang Rong Xu Ruidi Li Shisen Huang Hongbin Zhu Xinyan Liu |
| author_sort | Jibing Chen |
| collection | DOAJ |
| description | Aluminum alloy is an important material used in railway train structures. It is of great significance to repair aluminum alloy through directional energy deposition to reduce cost and improve the performance of the aluminum alloy. In this study, 7N01 aluminum alloy was repaired by means of laser-directed energy deposition (DED) with the powder of Sc-modified Al-Zn-Mg aluminum alloy as raw material. The microstructure and mechanical properties of the repaired specimens were studied through the metallographic microscope, scanning electron microscope, electron backscatter diffraction, universal tensile test, and Vickers hardness test in combination. The results show that the bonding interface of the repaired aluminum alloy is satisfactory, and the porosity is 2.8%. The grains in the repaired area are the columnar crystals growing vertically along the boundary of the melt pool with an obvious temperature gradient. Fine equiaxed crystals are distributed along the boundary of the melt pool, and Al<sub>3</sub>(Sc,Zr) particles play a role in grain refinement. The average grain size of the fine grain area in the repair zone next to the fusion zone is 9.1 μm, and the average grain size of the coarse grain area is 20 μm. The average tensile strength in the area of repair approaches 349 MPa, which is 91% that of the base material, and the elongation rate is 10.9%, which is 53.2% that of the base material. The hardness ranges between 122 HV and 131 HV, which is comparable to the base material. However, there is a significant decrease in the tensile strength and hardness of the base material (heat-affected zone). |
| first_indexed | 2024-03-11T03:30:20Z |
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| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-11T03:30:20Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
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| series | Metals |
| spelling | doaj.art-6386a67e86c34a83ad9478d42fba40d62023-11-18T02:26:26ZengMDPI AGMetals2075-47012023-04-0113582910.3390/met13050829Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-MgJibing Chen0Shanji Yu1Junsheng Yang2Rong Xu3Ruidi Li4Shisen Huang5Hongbin Zhu6Xinyan Liu7School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 420023, ChinaSchool of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 420023, ChinaSchool of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 420023, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaSchool of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 420023, ChinaCRRC Industrial Research Institute, Beijing 100053, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaAluminum alloy is an important material used in railway train structures. It is of great significance to repair aluminum alloy through directional energy deposition to reduce cost and improve the performance of the aluminum alloy. In this study, 7N01 aluminum alloy was repaired by means of laser-directed energy deposition (DED) with the powder of Sc-modified Al-Zn-Mg aluminum alloy as raw material. The microstructure and mechanical properties of the repaired specimens were studied through the metallographic microscope, scanning electron microscope, electron backscatter diffraction, universal tensile test, and Vickers hardness test in combination. The results show that the bonding interface of the repaired aluminum alloy is satisfactory, and the porosity is 2.8%. The grains in the repaired area are the columnar crystals growing vertically along the boundary of the melt pool with an obvious temperature gradient. Fine equiaxed crystals are distributed along the boundary of the melt pool, and Al<sub>3</sub>(Sc,Zr) particles play a role in grain refinement. The average grain size of the fine grain area in the repair zone next to the fusion zone is 9.1 μm, and the average grain size of the coarse grain area is 20 μm. The average tensile strength in the area of repair approaches 349 MPa, which is 91% that of the base material, and the elongation rate is 10.9%, which is 53.2% that of the base material. The hardness ranges between 122 HV and 131 HV, which is comparable to the base material. However, there is a significant decrease in the tensile strength and hardness of the base material (heat-affected zone).https://www.mdpi.com/2075-4701/13/5/829Sc modificationDEDmicrostructuremechanical propertyheat-affected zone |
| spellingShingle | Jibing Chen Shanji Yu Junsheng Yang Rong Xu Ruidi Li Shisen Huang Hongbin Zhu Xinyan Liu Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg Metals Sc modification DED microstructure mechanical property heat-affected zone |
| title | Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg |
| title_full | Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg |
| title_fullStr | Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg |
| title_full_unstemmed | Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg |
| title_short | Research on the Microstructure and Mechanical Properties of Repaired 7N01 Aluminum Alloy by Laser-Directed Energy Deposition with Sc Modified Al-Zn-Mg |
| title_sort | research on the microstructure and mechanical properties of repaired 7n01 aluminum alloy by laser directed energy deposition with sc modified al zn mg |
| topic | Sc modification DED microstructure mechanical property heat-affected zone |
| url | https://www.mdpi.com/2075-4701/13/5/829 |
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