Due to poor metallurgical weldability of magnesium alloy,laser welding crack is still one of the main defects.The generations of welding crack seriously affected the weld quality and reduce the mechanical properties o...Due to poor metallurgical weldability of magnesium alloy,laser welding crack is still one of the main defects.The generations of welding crack seriously affected the weld quality and reduce the mechanical properties of welded joints which have become a bottleneck of the magnesium alloy products widely used in the structure materials.In this paper,AZ31B magnesium alloy sheet with 2mm thickness was used for this investigation.The forming reason and extending characteristics of the welding cracks were investigated during the Nd:YAG pulsed laser welding.The results show that welding cracks are mainly solidification crack which were always present in the weld centers.Few welding hot cracks appear multiple furcation phenomenons,and main and branch cracks were intercrystalline crack.The partial branch crack was mixed intercrystalline and transgranular extension.In addition,few cracks in the weld were caused due to irregular shape porosity and inclusion.The delayed crack weren't observed in the weld after deposited 48 hours.In the pre-process on the basis,the characteristics and generation mechanism of YAG pulsed laser welding cracks of magnesium alloy were analyzed further.展开更多
Biodegradable magnesium-based alloys are very promising materials for temporary implants. Laser welding is an important joining method in such application. In this study, the as-rolled AZ31B magnesium alloy sheets of ...Biodegradable magnesium-based alloys are very promising materials for temporary implants. Laser welding is an important joining method in such application. In this study, the as-rolled AZ31B magnesium alloy sheets of 1 mm in thickness were successfully joined by Nd ： YAG laser welding. The microstructure and properties of the welded joint were investigated. The result shows that the welded joint is characterized by a narrow heat-affected zone, finer grains and a large number of precipitates distribute in the matrix in the weld. Microhardness of the weld is significantly improved to 72 HV 0. 05 as compared to 55 HV 0. 05 of the base metal. Tensile strength of butt-welded joint is 180. 24 MPa, which is 76. 8% that of the base metal. The electrochemical corrosion experiment shows that the corrosion resistance of laser welded joint is significantly improved in a 3.5 wt. % NaCl solution.展开更多
文摘Due to poor metallurgical weldability of magnesium alloy,laser welding crack is still one of the main defects.The generations of welding crack seriously affected the weld quality and reduce the mechanical properties of welded joints which have become a bottleneck of the magnesium alloy products widely used in the structure materials.In this paper,AZ31B magnesium alloy sheet with 2mm thickness was used for this investigation.The forming reason and extending characteristics of the welding cracks were investigated during the Nd:YAG pulsed laser welding.The results show that welding cracks are mainly solidification crack which were always present in the weld centers.Few welding hot cracks appear multiple furcation phenomenons,and main and branch cracks were intercrystalline crack.The partial branch crack was mixed intercrystalline and transgranular extension.In addition,few cracks in the weld were caused due to irregular shape porosity and inclusion.The delayed crack weren't observed in the weld after deposited 48 hours.In the pre-process on the basis,the characteristics and generation mechanism of YAG pulsed laser welding cracks of magnesium alloy were analyzed further.
基金The work was supported by the National Natural Science Foundation of China （ Grant No. 51305292 ） and the Aviation Science Foundation （ Grant No. 20105429001 ）.
文摘Biodegradable magnesium-based alloys are very promising materials for temporary implants. Laser welding is an important joining method in such application. In this study, the as-rolled AZ31B magnesium alloy sheets of 1 mm in thickness were successfully joined by Nd ： YAG laser welding. The microstructure and properties of the welded joint were investigated. The result shows that the welded joint is characterized by a narrow heat-affected zone, finer grains and a large number of precipitates distribute in the matrix in the weld. Microhardness of the weld is significantly improved to 72 HV 0. 05 as compared to 55 HV 0. 05 of the base metal. Tensile strength of butt-welded joint is 180. 24 MPa, which is 76. 8% that of the base metal. The electrochemical corrosion experiment shows that the corrosion resistance of laser welded joint is significantly improved in a 3.5 wt. % NaCl solution.
