In the current microwelding process using femtosecond(fs) laser between dissimilar materials,surface polishing and pressure assistance,so-called optical contact,are believed necessary.In this paper,direct welding of s...In the current microwelding process using femtosecond(fs) laser between dissimilar materials,surface polishing and pressure assistance,so-called optical contact,are believed necessary.In this paper,direct welding of soda lime glass and Kovar alloy using a fs laser is investigated to overcome the limit of optical contact.The processing of fs laser welding is comprehensively studied by varying the laser power,welding velocity and the number of welding.The shear joining strength is as high as 2 MPa.The cross-section of glass-Kovar alloy joints,the elemental diffusion and the fracture behavior of welded joints were studied.The results show that the fs laser irradiates the surface of Kovar alloy,micron/nanometer-sized metal particles are generated.These particles perform the role as an adhesive part in the welding process.It is believed that the Si atoms diffuses to Kovar alloy from the glass and partially replaces the Fe^(2+) ions on the surface of Kovar alloy,indicating that the mixing and interdiffusion of materials have occurred during the welding process.Finally,the welded sample was tested and has excellent water resistance and sealing property.Furthermore,to justify that this method can be applied to other stack ups,the glass-copper,the glass-Al6063 and sapphire-ceramic are also welded together.This work greatly simplifies the fs laser microwelding process and promotes its industrial applications,such as optoelectronic devices,medical devices and MEMS.展开更多
The surface morphology, cross-sections, and joint break force（JBF） of joints welded under different electrode forces were studied. The defects, such as electrode sticking, notch, and excessive expulsions, were obser...The surface morphology, cross-sections, and joint break force（JBF） of joints welded under different electrode forces were studied. The defects, such as electrode sticking, notch, and excessive expulsions, were observed in the joints. No desirable joints were achieved with the consideration of weld geometries and joint performances. From the cross-sectional morphology, the joint evolution during the RMW of Pt alloy and 316 LVM SS wires was developed, which involved cold collapse and heat promoted set-down of Pt alloy wire, unbalanced heating at interface, molten phase squeezed out, and defect formation. Finally, the defect formation was also discussed.展开更多
基金Project(GKZY2119502) supported by the Special Funds for Local Scientific and Technological Development guided by the Central Government,ChinaProject(JGY2021001) supported by the Innovation Project of Guangxi Graduate Education,China。
文摘In the current microwelding process using femtosecond(fs) laser between dissimilar materials,surface polishing and pressure assistance,so-called optical contact,are believed necessary.In this paper,direct welding of soda lime glass and Kovar alloy using a fs laser is investigated to overcome the limit of optical contact.The processing of fs laser welding is comprehensively studied by varying the laser power,welding velocity and the number of welding.The shear joining strength is as high as 2 MPa.The cross-section of glass-Kovar alloy joints,the elemental diffusion and the fracture behavior of welded joints were studied.The results show that the fs laser irradiates the surface of Kovar alloy,micron/nanometer-sized metal particles are generated.These particles perform the role as an adhesive part in the welding process.It is believed that the Si atoms diffuses to Kovar alloy from the glass and partially replaces the Fe^(2+) ions on the surface of Kovar alloy,indicating that the mixing and interdiffusion of materials have occurred during the welding process.Finally,the welded sample was tested and has excellent water resistance and sealing property.Furthermore,to justify that this method can be applied to other stack ups,the glass-copper,the glass-Al6063 and sapphire-ceramic are also welded together.This work greatly simplifies the fs laser microwelding process and promotes its industrial applications,such as optoelectronic devices,medical devices and MEMS.
基金Funded by the National Natural Science Foundation of China(No.51365044)the State Key Laboratory for Mechanical Behavior of Materials(No.20111203)the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology(No.AWJ-M13-09)
文摘The surface morphology, cross-sections, and joint break force（JBF） of joints welded under different electrode forces were studied. The defects, such as electrode sticking, notch, and excessive expulsions, were observed in the joints. No desirable joints were achieved with the consideration of weld geometries and joint performances. From the cross-sectional morphology, the joint evolution during the RMW of Pt alloy and 316 LVM SS wires was developed, which involved cold collapse and heat promoted set-down of Pt alloy wire, unbalanced heating at interface, molten phase squeezed out, and defect formation. Finally, the defect formation was also discussed.
