A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld mi...A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated.It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter.DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld.The recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was GDRX.DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base material.Moreover,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min.It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.展开更多
The mechanical properties and microstructural distribution of the Cu/A1 brazing joints formed by torch-brazing with different Zn-A1 filler metals were investigated. The microstructure of the Zn-A1 alloys was studied b...The mechanical properties and microstructural distribution of the Cu/A1 brazing joints formed by torch-brazing with different Zn-A1 filler metals were investigated. The microstructure of the Zn-A1 alloys was studied by optical microscopy and scanning electron microscopy, and the phase constitution of the Cu/A1 joints was analyzed by energy dispersion spectrometry. The results show that the spreading area of the Zn-A1 filler metals on the Cu and A1 substrates increases as the A1 content increases. The mechanical results indicate that the shear strength reaches a peak value of 88 MPa when A1 and Cu are brazed with Zn-15AI filler metal. Microhardness levels from HV122 to HV515 were produced in the three brazing seam regions corresponding to various microstructure features. The Zn- and Al-rich phases exist in the middle brazing seam regions. However, two interface layers, CuZn3 and A12Cu are formed on the Cu side when the A1 content in the filler metals is 2% and more than 15%, respectively. The relationship between intermetallic compounds on Cu side and Zn-xA1 filler metals was investigated.展开更多
To design a promising Al−Si filler alloy with a relatively low melting-point,good strength and plasticity for the Cu/Al joint,the Cu,Ni,Zr and Er elements were innovatively added to modify the traditional Al−Si eutect...To design a promising Al−Si filler alloy with a relatively low melting-point,good strength and plasticity for the Cu/Al joint,the Cu,Ni,Zr and Er elements were innovatively added to modify the traditional Al−Si eutectic filler.The microstructure and mechanical properties of filler alloys and Cu/Al joints were investigated.The result indicated that the Al−Si−Ni−Cu filler alloys mainly consisted of Al(s,s),Al_(2)(Cu,Ni)and Si(s,s).The Al−10Si−2Ni−6Cu filler alloy exhibited relatively low solidus(521℃)and liquidus(577℃)temperature,good tensile strength(305.8 MPa)and fracture elongation(8.5%).The corresponding Cu/Al joint brazed using Al−10Si−2Ni−6Cu filler was mainly composed of Al_(8)(Mn,Fe)_(2)Si,Al_(2)(Cu,Ni)3,Al(Cu,Ni),Al_(2)(Cu,Ni)and Al(s,s),yielding a shear strength of(90.3±10.7)MPa.The joint strength was further improved to(94.6±2.5)MPa when the joint was brazed using the Al−10Si−2Ni−6Cu−0.2Er−0.2Zr filler alloy.Consequently,the(Cu,Ni,Zr,Er)-modified Al−Si filler alloy was suitable for obtaining high-quality Cu/Al brazed joints.展开更多
Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173-1273 K for 60-1800 s. When products are brazed, the optimum brazing parameters are as follows： brazing temperature is 1215-1225 K; brazing ti...Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173-1273 K for 60-1800 s. When products are brazed, the optimum brazing parameters are as follows： brazing temperature is 1215-1225 K; brazing time is 250-300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu （Ti3Al（Cu）） formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al（Cu） and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interracial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al（Cu）/TiCu/Cu3P/Cu solid solution （Cu3P）/Cu3P/TiCu/Ti3Al（Cu）/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu＋Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity/to of reaction layer TiCu＋Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 kJ/mol and 0.0821 m2/s, respectively, and growth formula was y2=O.O821exp（-34421.59/T）t.Careful control of the growth for the reaction layer TiCu＋Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu＋Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.展开更多
Mo-Cu composite and Cr18-Ni8 stainless steel were brazed with Ni-Cr-P filler metal in a vacuum of 10-4 Pa and a Mo-Cu/Cr18-Ni8 joint was obtained. Microstructure in Mo-Cu/Cr18-Ni8 joint was investigated by field-emiss...Mo-Cu composite and Cr18-Ni8 stainless steel were brazed with Ni-Cr-P filler metal in a vacuum of 10-4 Pa and a Mo-Cu/Cr18-Ni8 joint was obtained. Microstructure in Mo-Cu/Cr18-Ni8 joint was investigated by field-emission scanning electron microscope( FE-SEM) with energy dispersive spectrometer( EDS). Shear strength of Mo-Cu/Cr18-Ni8 lap joint was measured by electromechanical universal testing machine. An excellent Mo-Cu/Cr18-Ni8 joint with a shear strength of 155 MPa was achieved at 980 ℃ for 20 min. Brazed joint was mainly comprised of eutectic structure in the center of brazing seam,matrix structure and lump structure. Ni-Cu( Mo) and Ni-Fe solid solution were at the interface beside Mo-Cu composite and Cr18-Ni8 stainless steel,respectively. Shear fracture exhibited mixed ductile-brittle fracture feature with trans-granular fracture,ductile dimples and tearing edges. Fracture originated from the interface between brazing seam and Mo-Cu composite.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52275349,52035005)Key Research and Development Program of Shandong Province of China(Grant No.2021ZLGX01)Qilu Young Scholar Program of Shandong University of China.
文摘A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated.It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter.DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld.The recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was GDRX.DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base material.Moreover,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min.It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.
基金Project (2009GJC20040) supported by the Scientist and Technician Serve the Enterprise,MOST,China
文摘The mechanical properties and microstructural distribution of the Cu/A1 brazing joints formed by torch-brazing with different Zn-A1 filler metals were investigated. The microstructure of the Zn-A1 alloys was studied by optical microscopy and scanning electron microscopy, and the phase constitution of the Cu/A1 joints was analyzed by energy dispersion spectrometry. The results show that the spreading area of the Zn-A1 filler metals on the Cu and A1 substrates increases as the A1 content increases. The mechanical results indicate that the shear strength reaches a peak value of 88 MPa when A1 and Cu are brazed with Zn-15AI filler metal. Microhardness levels from HV122 to HV515 were produced in the three brazing seam regions corresponding to various microstructure features. The Zn- and Al-rich phases exist in the middle brazing seam regions. However, two interface layers, CuZn3 and A12Cu are formed on the Cu side when the A1 content in the filler metals is 2% and more than 15%, respectively. The relationship between intermetallic compounds on Cu side and Zn-xA1 filler metals was investigated.
基金the financial support from the Primary Research&Development Plan of Zhejiang Province,China(No.2021C01178)the National MCF Energy R&D Program,China(No.2019YFE03100400)+1 种基金the National Natural Science Foundation of China(Nos.51705457,51975530,52005445,52175368)the Natural Science Foundation of Zhejiang Province,China(Nos.LQ21E050015,LQ21E050018).
文摘To design a promising Al−Si filler alloy with a relatively low melting-point,good strength and plasticity for the Cu/Al joint,the Cu,Ni,Zr and Er elements were innovatively added to modify the traditional Al−Si eutectic filler.The microstructure and mechanical properties of filler alloys and Cu/Al joints were investigated.The result indicated that the Al−Si−Ni−Cu filler alloys mainly consisted of Al(s,s),Al_(2)(Cu,Ni)and Si(s,s).The Al−10Si−2Ni−6Cu filler alloy exhibited relatively low solidus(521℃)and liquidus(577℃)temperature,good tensile strength(305.8 MPa)and fracture elongation(8.5%).The corresponding Cu/Al joint brazed using Al−10Si−2Ni−6Cu filler was mainly composed of Al_(8)(Mn,Fe)_(2)Si,Al_(2)(Cu,Ni)3,Al(Cu,Ni),Al_(2)(Cu,Ni)and Al(s,s),yielding a shear strength of(90.3±10.7)MPa.The joint strength was further improved to(94.6±2.5)MPa when the joint was brazed using the Al−10Si−2Ni−6Cu−0.2Er−0.2Zr filler alloy.Consequently,the(Cu,Ni,Zr,Er)-modified Al−Si filler alloy was suitable for obtaining high-quality Cu/Al brazed joints.
基金This research was financially supported by the National Natural Science Foundation of China(No.50325517).
文摘Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173-1273 K for 60-1800 s. When products are brazed, the optimum brazing parameters are as follows： brazing temperature is 1215-1225 K; brazing time is 250-300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu （Ti3Al（Cu）） formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al（Cu） and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interracial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al（Cu）/TiCu/Cu3P/Cu solid solution （Cu3P）/Cu3P/TiCu/Ti3Al（Cu）/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu＋Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity/to of reaction layer TiCu＋Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 kJ/mol and 0.0821 m2/s, respectively, and growth formula was y2=O.O821exp（-34421.59/T）t.Careful control of the growth for the reaction layer TiCu＋Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu＋Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.
基金supported by Shandong Natural Science Foundation(ZR2015EM040)
文摘Mo-Cu composite and Cr18-Ni8 stainless steel were brazed with Ni-Cr-P filler metal in a vacuum of 10-4 Pa and a Mo-Cu/Cr18-Ni8 joint was obtained. Microstructure in Mo-Cu/Cr18-Ni8 joint was investigated by field-emission scanning electron microscope( FE-SEM) with energy dispersive spectrometer( EDS). Shear strength of Mo-Cu/Cr18-Ni8 lap joint was measured by electromechanical universal testing machine. An excellent Mo-Cu/Cr18-Ni8 joint with a shear strength of 155 MPa was achieved at 980 ℃ for 20 min. Brazed joint was mainly comprised of eutectic structure in the center of brazing seam,matrix structure and lump structure. Ni-Cu( Mo) and Ni-Fe solid solution were at the interface beside Mo-Cu composite and Cr18-Ni8 stainless steel,respectively. Shear fracture exhibited mixed ductile-brittle fracture feature with trans-granular fracture,ductile dimples and tearing edges. Fracture originated from the interface between brazing seam and Mo-Cu composite.
基金supported by the National Natural Science Foundation of China(Nos.51871128,51875300)the Natural Science Foundation of Shandong Province,China(No.ZR2018MEE017)+1 种基金Local Science and Technology Development Projects Guided by the Central Government,China(No.YDZX20203700003578)2021 Major Industrial Key Project of Transformation of Old and New Driving Forces in Shandong Province,China。
