Gaoyang Mi
Huazhong University of Science and Technology
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Publication
Featured researches published by Gaoyang Mi.
Journal of Laser Applications | 2018
Lingda Xiong; Gaoyang Mi; Chunming Wang
Laser welding was applied to join 2-mm-thick dissimilar titanium alloys, Ti-22Al-25Nb (at. %) and Ti-6Al-4V (wt. %). Defect-free joints were obtained. The microstructures and mechanical properties of the welded joints were investigated. The results showed that the fusion zone mainly consisted of B2 phase and martensite α′ phase. The heat-affected zone microstructures of Ti-22Al-25Nb and Ti-6Al-4V were different because of the different base metal. The heat-affected zone of Ti-22Al-25Nb mainly consisted of B2 phase, O phase, and α2 phase, whereas the heat-affected zone of Ti-6Al-4V mainly consisted of α phase, β phase, and martensite α′ phase. EDS (Energy Dispersive Spectroscopy) results showed that the element distribution of each titanium alloy heat-affected zone and fusion zone was similar without an obvious change. Due to severe agitation, the element distribution was even. Different microstructures in different heat-affected zones resulted in an unsymmetrical hardness distribution. The hardness of fusion zone was the lowest of around 300 HV when the hardness of Ti-6Al-4V heat-affected zone near fusion zone was the highest of around 400 HV due to the influence of martensite α′ phase. In tensile tests performed at room temperature and 650 °C, the tensile strength of the joint reached 1057 and 363 MPa, respectively. Both these joints fractured at the fusion zone.Laser welding was applied to join 2-mm-thick dissimilar titanium alloys, Ti-22Al-25Nb (at. %) and Ti-6Al-4V (wt. %). Defect-free joints were obtained. The microstructures and mechanical properties of the welded joints were investigated. The results showed that the fusion zone mainly consisted of B2 phase and martensite α′ phase. The heat-affected zone microstructures of Ti-22Al-25Nb and Ti-6Al-4V were different because of the different base metal. The heat-affected zone of Ti-22Al-25Nb mainly consisted of B2 phase, O phase, and α2 phase, whereas the heat-affected zone of Ti-6Al-4V mainly consisted of α phase, β phase, and martensite α′ phase. EDS (Energy Dispersive Spectroscopy) results showed that the element distribution of each titanium alloy heat-affected zone and fusion zone was similar without an obvious change. Due to severe agitation, the element distribution was even. Different microstructures in different heat-affected zones resulted in an unsymmetrical hardness distribution. The hardness of fus...
Journal of Laser Applications | 2018
Xiong Zhang; Gaoyang Mi; Chunming Wang
Hybrid laser-arc welding is an emerging welding technology that has a promising prospect in large-scale equipment manufacturing. In this paper, the butt joint of 316L austenitic stainless steel with 40 mm was made by using the multi-layer hybrid laser-arc welding process. On this basis, microstructure and properties of the welded joint were further investigated using an optical microscope, scanning electron microscope, and other methodologies. The results showed that the base materials consist of massive polygonal austenitic with a small amount of ferrites distributed in the grain boundary. What is more, the 316L austenitic stainless steel was heated and solidified in an F-A mode. Thus, ferrites distributed in the grain boundary were coarsened in the heat affected zone and the fusion zone was also composed of massive austenite and ferrites, which were approximately perpendicular to the fusion line. Owing to the different thermal cycles of different layers, the microstructure of the upper layer was coarser than that of the lower layer, and this microstructural inhomogeneity led to the variation of the hardness within the welded joint: hardness value of the upper weld was slightly higher than that of the lower weld. In addition, all tensile specimens were failed at the fusion zone and showed an obvious characteristic of ductile fracture with massive dimples distributing on it. Consequently, this study will broaden the scope of the application for the thick-plate hybrid laser-arc welding technology.Hybrid laser-arc welding is an emerging welding technology that has a promising prospect in large-scale equipment manufacturing. In this paper, the butt joint of 316L austenitic stainless steel with 40 mm was made by using the multi-layer hybrid laser-arc welding process. On this basis, microstructure and properties of the welded joint were further investigated using an optical microscope, scanning electron microscope, and other methodologies. The results showed that the base materials consist of massive polygonal austenitic with a small amount of ferrites distributed in the grain boundary. What is more, the 316L austenitic stainless steel was heated and solidified in an F-A mode. Thus, ferrites distributed in the grain boundary were coarsened in the heat affected zone and the fusion zone was also composed of massive austenite and ferrites, which were approximately perpendicular to the fusion line. Owing to the different thermal cycles of different layers, the microstructure of the upper layer was coarser...
DEStech Transactions on Materials Science and Engineering | 2017
Wei Liu; Yuewe Ai; Ping Jiang; Yang Liu; Gaoyang Mi
In this paper, a numerical model is proposed to investigate the keyhole dynamic behaviors and the formation process of hump. Both of the welding processes with and without shielding gas are calculated during the simulation. It is revealed that the hump generated in the weld is caused by the metal flows in the rear part of the keyhole aperture driven by the resultant force of surface tension, recoil pressure and buoyance force. The shielding gas can significantly change the fluid flows in the molten pool and hence suppress the formation of the hump. The proposed method is validated by the confirmation experiments and good agreement between the simulated and experimental results have been found.
The International Journal of Advanced Manufacturing Technology | 2016
Ruoyang Li; Jun Yue; Ran Sun; Gaoyang Mi; Chunming Wang; Xinyu Shao
Optics and Laser Technology | 2017
Sang Liu; Gaoyang Mi; Fei Yan; Chunming Wang; Ping Jiang
Applied Thermal Engineering | 2017
Yuewei Ai; Ping Jiang; Xinyu Shao; Peigen Li; Chunming Wang; Gaoyang Mi; Shaoning Geng; Yang Liu; Wei Liu
Journal of Materials Processing Technology | 2016
Gaoyang Mi; Lingda Xiong; Chunming Wang; Xiyuan Hu; Yanhong Wei
Optics and Lasers in Engineering | 2017
Xiang Xu; Gaoyang Mi; Yuanqing Luo; Ping Jiang; Xinyu Shao; Chunming Wang
Results in physics | 2017
Longchao Cao; Yang Yang; Ping Jiang; Qi Zhou; Gaoyang Mi; Zhongmei Gao; Youmin Rong; Chunming Wang
Materials & Design | 2016
Yuewei Ai; Ping Jiang; Xinyu Shao; Chunming Wang; Peigen Li; Gaoyang Mi; Yang Liu; Wei Liu