Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy
Fiber welding of socket-joints made of nanostructured high-performance molybdenum alloy (NS Mo) was carried out to get a better understanding of the role of welding heat input. It was found that low heat input (i.e., high welding speed) resulted in significantly refined grains in the fusion zone (FZ...
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MDPI AG
2019-06-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/9/6/640 |
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| author | Miao-Xia Xie Yan-Xin Li Xiang-Tao Shang Xue-Wu Wang Jun-Yu Pei |
| author_facet | Miao-Xia Xie Yan-Xin Li Xiang-Tao Shang Xue-Wu Wang Jun-Yu Pei |
| author_sort | Miao-Xia Xie |
| collection | DOAJ |
| description | Fiber welding of socket-joints made of nanostructured high-performance molybdenum alloy (NS Mo) was carried out to get a better understanding of the role of welding heat input. It was found that low heat input (i.e., high welding speed) resulted in significantly refined grains in the fusion zone (FZ) of fiber laser welded NS Mo joints. When welding heat input decreased from 3600 J/cm (i.e., 1.2 kW, 20 cm/min) to 250 J/cm (i.e., 2.5 kW, 600 cm/min), the tensile strength of welded joints increased from about 250 MPa to about 570 MPa. It was confirmed by energy spectrum analysis that the higher the welding heat input, the higher the oxygen contents at the grain boundary (GB) within the FZ. In addition, the most important reason for poor strength of welded joints of Mo alloys was reported as being that MoO<sub>2</sub> was segregated on the grain boundary. Therefore, it was concluded that welding under low heat input (i.e., high welding speed) was able to reduce the segregation degree of MoO<sub>2</sub> at the grain boundary by refining grains and increasing the total area of GBs, thus improving the strength of welded joints and reducing the proportion of the intergranular fracture zone in tensile fractures. |
| first_indexed | 2024-12-11T07:46:07Z |
| format | Article |
| id | doaj.art-a3169835e7fc4ac38e2f0205c5a931f0 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-12-11T07:46:07Z |
| publishDate | 2019-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-a3169835e7fc4ac38e2f0205c5a931f02022-12-22T01:15:28ZengMDPI AGMetals2075-47012019-06-019664010.3390/met9060640met9060640Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum AlloyMiao-Xia Xie0Yan-Xin Li1Xiang-Tao Shang2Xue-Wu Wang3Jun-Yu Pei4School of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, ChinaSchool of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, ChinaSchool of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, ChinaSchool of Information Science and Engineering, East China University of Science and Technology, Shanghai 200237, ChinaState Key Laboratory of Mechanical Behavior for Materials, Xi’an JiaoTong University, Xi’ann 710049, ChinaFiber welding of socket-joints made of nanostructured high-performance molybdenum alloy (NS Mo) was carried out to get a better understanding of the role of welding heat input. It was found that low heat input (i.e., high welding speed) resulted in significantly refined grains in the fusion zone (FZ) of fiber laser welded NS Mo joints. When welding heat input decreased from 3600 J/cm (i.e., 1.2 kW, 20 cm/min) to 250 J/cm (i.e., 2.5 kW, 600 cm/min), the tensile strength of welded joints increased from about 250 MPa to about 570 MPa. It was confirmed by energy spectrum analysis that the higher the welding heat input, the higher the oxygen contents at the grain boundary (GB) within the FZ. In addition, the most important reason for poor strength of welded joints of Mo alloys was reported as being that MoO<sub>2</sub> was segregated on the grain boundary. Therefore, it was concluded that welding under low heat input (i.e., high welding speed) was able to reduce the segregation degree of MoO<sub>2</sub> at the grain boundary by refining grains and increasing the total area of GBs, thus improving the strength of welded joints and reducing the proportion of the intergranular fracture zone in tensile fractures.https://www.mdpi.com/2075-4701/9/6/640high-performance molybdenum alloyfiber weldingheat inputmicrostructuremechanical propertiesgrain boundary segregation |
| spellingShingle | Miao-Xia Xie Yan-Xin Li Xiang-Tao Shang Xue-Wu Wang Jun-Yu Pei Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy Metals high-performance molybdenum alloy fiber welding heat input microstructure mechanical properties grain boundary segregation |
| title | Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy |
| title_full | Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy |
| title_fullStr | Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy |
| title_full_unstemmed | Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy |
| title_short | Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy |
| title_sort | microstructure and mechanical properties of a fiber welded socket joint made of powder metallurgy molybdenum alloy |
| topic | high-performance molybdenum alloy fiber welding heat input microstructure mechanical properties grain boundary segregation |
| url | https://www.mdpi.com/2075-4701/9/6/640 |
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