Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding
In this study, 2198 Al-Li alloy, a low density and high-performance material for aerospace equipment, was welded using ultrahigh-frequency pulse alternating current with cold metal transfer (UHF-ACCMT). Influence of different ultrahigh-frequency on the formation, porosity, microstructure, microhardn...
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MDPI AG
2018-12-01
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| Online Access: | http://www.mdpi.com/1996-1944/12/1/79 |
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| author | Liwei Wang Yingchao Suo Chaofeng Wu Dianlong Wang Zhimin Liang |
| author_facet | Liwei Wang Yingchao Suo Chaofeng Wu Dianlong Wang Zhimin Liang |
| author_sort | Liwei Wang |
| collection | DOAJ |
| description | In this study, 2198 Al-Li alloy, a low density and high-performance material for aerospace equipment, was welded using ultrahigh-frequency pulse alternating current with cold metal transfer (UHF-ACCMT). Influence of different ultrahigh-frequency on the formation, porosity, microstructure, microhardness and tensile strength of the welded joints were investigated. The results showed that the coupled ultrahigh-frequency current generated electromagnetic force to stir the liquid metal of molten pool. The weld formation became much better with metallic luster and uniform ripples at frequency of 60 kHz and 70 kHz. The porosity was the minimum at frequency of 60 kHz. Furthermore, the molten pool was scoured and stirred by the electromagnetic force which provided the thermal and dynamic conditions for nucleation and grain refinement, the width of fine equiaxed grain zone became larger, and the number of equiaxed non-dendrite grains increased. With the grain refining and crystallize transition, the average microhardness and tensile strength of the joints at frequency of 60 kHz reached up the highest value, 116 HV0.1 and 338 MPa, respectively. The fracture of the welded joints presented the characteristics of quasi-cleavage fracture. |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-04-12T11:56:11Z |
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| spelling | doaj.art-aa6ea730e3e84e388b076944f940a2d02022-12-22T03:33:59ZengMDPI AGMaterials1996-19442018-12-011217910.3390/ma12010079ma12010079Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT WeldingLiwei Wang0Yingchao Suo1Chaofeng Wu2Dianlong Wang3Zhimin Liang4School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, ChinaSchool of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, ChinaSchool of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, ChinaSchool of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, ChinaSchool of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, ChinaIn this study, 2198 Al-Li alloy, a low density and high-performance material for aerospace equipment, was welded using ultrahigh-frequency pulse alternating current with cold metal transfer (UHF-ACCMT). Influence of different ultrahigh-frequency on the formation, porosity, microstructure, microhardness and tensile strength of the welded joints were investigated. The results showed that the coupled ultrahigh-frequency current generated electromagnetic force to stir the liquid metal of molten pool. The weld formation became much better with metallic luster and uniform ripples at frequency of 60 kHz and 70 kHz. The porosity was the minimum at frequency of 60 kHz. Furthermore, the molten pool was scoured and stirred by the electromagnetic force which provided the thermal and dynamic conditions for nucleation and grain refinement, the width of fine equiaxed grain zone became larger, and the number of equiaxed non-dendrite grains increased. With the grain refining and crystallize transition, the average microhardness and tensile strength of the joints at frequency of 60 kHz reached up the highest value, 116 HV0.1 and 338 MPa, respectively. The fracture of the welded joints presented the characteristics of quasi-cleavage fracture.http://www.mdpi.com/1996-1944/12/1/79AC CMTultrahigh-frequency pulse current2198 Al-Li alloymicrostructuremechanical properties |
| spellingShingle | Liwei Wang Yingchao Suo Chaofeng Wu Dianlong Wang Zhimin Liang Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding Materials AC CMT ultrahigh-frequency pulse current 2198 Al-Li alloy microstructure mechanical properties |
| title | Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding |
| title_full | Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding |
| title_fullStr | Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding |
| title_full_unstemmed | Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding |
| title_short | Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding |
| title_sort | effect of pulse frequency on microstructure and mechanical properties of 2198 al li alloy joints obtained by ultrahigh frequency pulse ac cmt welding |
| topic | AC CMT ultrahigh-frequency pulse current 2198 Al-Li alloy microstructure mechanical properties |
| url | http://www.mdpi.com/1996-1944/12/1/79 |
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