Amorphous filler Ti-Zr-Cu-Ni with better performance and higher melting point than the α → β phase transition temperature 882.5°C of TA2, is appropriate for joining TC and TB titanium alloys but not for TA t...Amorphous filler Ti-Zr-Cu-Ni with better performance and higher melting point than the α → β phase transition temperature 882.5°C of TA2, is appropriate for joining TC and TB titanium alloys but not for TA titanium alloys, with which the ductility of the joined base metal TA2 gets down. In this paper, Sn is added into Ti-Zr-Cu-Ni filler to reduce its melting temperature then to satisfy the joining temperature requirement, and the effects of the content of Sn on the microstructure of the alloy and brazing performance are investigated. The results show that, the Ti-Zr-Cu-Ni-Sn brazing foils still possess amorphous structure;the melting point of fillers is reducing with the increase of the Sn content;the joint gap that formed during brazing TA2 and Q235 using Ti-Zr-Cu-Ni-Sn foils is fully filled with continuous compact surface and smooth uniform fillet;the shear strength of the joint is raising with the increase of Sn content in brazing fillers and the strength reaches to 112 MPa when Sn content is 3%;adding more Sn, more brittle intermetallic compounds TiFe and TiFe2 are gathering to form cluster and the shear strength of the joint is reducing;the shear fracture always occurs in the center of the seam.展开更多
With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes t...With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes that are low cost,environmentally friendly,and highly flexible;the high-energy shock wave in a cavitation bubble's collapse process is used as the loading force.Herein,a new process for the microbulging of the water-jet cavitation is proposed.A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system.The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part.Subsequently,the effects of the main parameters of the water-jet cavitation on the bulging profile,forming depth,surface roughness,and bulging thickness distribution of TA2 titanium foil are revealed.The results show that the plastic deformation increases nonlinearly with the incident pressure.When the incident pressure is 20 MPa,the maximum deformation exceeds 240 pm,and the thickness thinning ratio changes within 10%.The microbulging feasibility of water-jet cavitation is verified by this phenomenon.展开更多
The anisotropic tensile mechanical properties of pure titanium(TA2)tubes were studied by means of theoretical analysis,finite element simulation and tensile tests.Based on the stress analysis of circumferential tensil...The anisotropic tensile mechanical properties of pure titanium(TA2)tubes were studied by means of theoretical analysis,finite element simulation and tensile tests.Based on the stress analysis of circumferential tensile of TA2 tube,an equation for calculating the tangential force of circumferential tensile specimen was established,and the relationship among tangential force,friction and position of ring specimen was analyzed.The finite element simulation analysis of circumferential tensile process of TA2 ring specimen was carried out,which verified the tangential force equation derived from theoretical analysis.The effect of gauge length and friction on necking and tensile load was analyzed,and the optimal gauge length was selected for the ring hoop tensile test.Finally,the axial and circumferential tensile digital image correlation experiments were carried out to verify the theoretical and finite element simulation results.The friction coefficient between TA2 tube and D-blocks(using Teflon lubricant)was determined by the inverse finite element method and the friction experiment,and the true stress-strain curve of TA2 tube was obtained.The results show that the axial and circumfere ntial mechanical behaviors of TA2 tubes are significantly different and an isotropic.展开更多
文摘Amorphous filler Ti-Zr-Cu-Ni with better performance and higher melting point than the α → β phase transition temperature 882.5°C of TA2, is appropriate for joining TC and TB titanium alloys but not for TA titanium alloys, with which the ductility of the joined base metal TA2 gets down. In this paper, Sn is added into Ti-Zr-Cu-Ni filler to reduce its melting temperature then to satisfy the joining temperature requirement, and the effects of the content of Sn on the microstructure of the alloy and brazing performance are investigated. The results show that, the Ti-Zr-Cu-Ni-Sn brazing foils still possess amorphous structure;the melting point of fillers is reducing with the increase of the Sn content;the joint gap that formed during brazing TA2 and Q235 using Ti-Zr-Cu-Ni-Sn foils is fully filled with continuous compact surface and smooth uniform fillet;the shear strength of the joint is raising with the increase of Sn content in brazing fillers and the strength reaches to 112 MPa when Sn content is 3%;adding more Sn, more brittle intermetallic compounds TiFe and TiFe2 are gathering to form cluster and the shear strength of the joint is reducing;the shear fracture always occurs in the center of the seam.
基金Supported by Nati onal Natural Science Foundation of China(Grant Nos.51575245,51679112)Jiangsu Province Key Research and Development Program of China(Grant No.BE2016161),Jiangsu Province"Six Tale nts Peak"Project of China(Grant No.XNYQC-002).
文摘With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes that are low cost,environmentally friendly,and highly flexible;the high-energy shock wave in a cavitation bubble's collapse process is used as the loading force.Herein,a new process for the microbulging of the water-jet cavitation is proposed.A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system.The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part.Subsequently,the effects of the main parameters of the water-jet cavitation on the bulging profile,forming depth,surface roughness,and bulging thickness distribution of TA2 titanium foil are revealed.The results show that the plastic deformation increases nonlinearly with the incident pressure.When the incident pressure is 20 MPa,the maximum deformation exceeds 240 pm,and the thickness thinning ratio changes within 10%.The microbulging feasibility of water-jet cavitation is verified by this phenomenon.
基金the financial supports of the National Natural Science Foundation of China(Nos.51675260 and 51475223)the Six Talents Peak Project of Jiangsu Province(No.20I4-ZBZZ-012).
文摘The anisotropic tensile mechanical properties of pure titanium(TA2)tubes were studied by means of theoretical analysis,finite element simulation and tensile tests.Based on the stress analysis of circumferential tensile of TA2 tube,an equation for calculating the tangential force of circumferential tensile specimen was established,and the relationship among tangential force,friction and position of ring specimen was analyzed.The finite element simulation analysis of circumferential tensile process of TA2 ring specimen was carried out,which verified the tangential force equation derived from theoretical analysis.The effect of gauge length and friction on necking and tensile load was analyzed,and the optimal gauge length was selected for the ring hoop tensile test.Finally,the axial and circumferential tensile digital image correlation experiments were carried out to verify the theoretical and finite element simulation results.The friction coefficient between TA2 tube and D-blocks(using Teflon lubricant)was determined by the inverse finite element method and the friction experiment,and the true stress-strain curve of TA2 tube was obtained.The results show that the axial and circumfere ntial mechanical behaviors of TA2 tubes are significantly different and an isotropic.
