Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental...Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental observations, the molten interlayer reacts vigorously with base metals, forming several continuous reaction layers. The typical interfacial microstructure of the joint can be expressed as GH99/（Ni,Cr）ss（γ）/TiNi（β2）＋TiNi2Al（τ4）＋Ti2Ni（δ）/δ＋Ti3Al（α2）＋Al3NiTi2（τ3）/α2＋τ3/TiAl. The maximum shear strength is 258 MPa for the specimen brazed at 1000°C for 10 min. Higher brazing temperature or longer brazing time causes coarsening of the phases in the brazing seam and formation of brittle intermetallic layer, which greatly depresses the shear strength of the joints.展开更多
A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?G...A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?Ge filler metals drops from 592 to 519 °C as the content of Ge increases from 0 to 30% (mass fraction). As the content of Ge increases, bright eutectic Ge forms. However, as the Ge content exceeds 20%, the aggregation growth of the eutectic structure tends to happen and coarsened primary Si?Ge particle forms, which is detrimental to the properties of alloys. The Al?10.8Si?10Ge filler metal has good processability and wettability with the base metal Al. When this filler metal is used to braze 1060 aluminum, the complete joint can be achieved. Furthermore, the shear strength test results show that the fracture of brazed joint with Al?10.8Si?10Ge filler metal occurs in the base metal.展开更多
The influence of brazing temperature and brazing time on the microstructure and shear strength ofγ-TiAl/GH536 joints brazed with Ti-Zr-Cu-Ni-Fe-Co-Mo filler was investigated using SEM,EDS,XRD and universal testing ma...The influence of brazing temperature and brazing time on the microstructure and shear strength ofγ-TiAl/GH536 joints brazed with Ti-Zr-Cu-Ni-Fe-Co-Mo filler was investigated using SEM,EDS,XRD and universal testing machine.Results show that all the brazed joints mainly consist of four reaction layers regardless of the brazing temperature and brazing time.The thickness of the brazed seam and the average shear strength of the joint increase firstly and then decrease with brazing temperature in the range of 1090-1170℃and brazing time varying from 0 to 20 min.The maximum shear strength of 262 MPa is obtained at 1150℃for 10 min.The brittle Al3NiTi2 and TiNi3 intermetallics are the main controlling factors for the crack generation and deterioration of joint strength.The fracture surface is characterized as typical cleavage fracture and it mainly consists of massive brittle Al3NiTi2 intermetallics.展开更多
In order to research the influence of Zr content （ below 15 wt. % ） on the properties of the filler metal. Ti-5Zr- 15Cu-15Ni-La, Ti-lOZr-15Cu-15Ni-La and Ti-15Zr-15Cu-15Ni-La filler metals were prepared. The wettabi...In order to research the influence of Zr content （ below 15 wt. % ） on the properties of the filler metal. Ti-5Zr- 15Cu-15Ni-La, Ti-lOZr-15Cu-15Ni-La and Ti-15Zr-15Cu-15Ni-La filler metals were prepared. The wettability of the filler metals on Ti-6Al-4V was evaluated and the melting temperatures of the filler metals were tested by differential scanning calorimetry （DSC）. The microstructures and mechanical properties of the brazed joints were investigated. The results show that the wettability of the filler metals improves as the Zr content increases. Zr content has great influence on the melting temperature of the filler metals. When Zr content changes from 5 wt. % to 10 wt. % and 15 wt. % , the melting temperature decreases about 80 ℃. The brazed joint with Ti-5Zr-15Cu-15Ni-La filler metal shows aciculate phase on the interfizce. The brazed joints with Ti-lOZr-15Cu-15Ni-La and Ti-15Zr-15Cu-15Ni-La filler metals consist of three zones, a segregated center zonc, diffusion reaction zone and acicular zone. The brazed joint with Ti-5Zr-15Cu-15Ni-La filler metal achieves the maximum shear strength 313.9 MPa.展开更多
Ti-Zr-Cu-Ni amorphous filler with good performance is suitable for joining TC and TB titanium alloy, but its melting temperature is higher than 882.5°C, the α→β phase transition temperature of TA2, which makes...Ti-Zr-Cu-Ni amorphous filler with good performance is suitable for joining TC and TB titanium alloy, but its melting temperature is higher than 882.5°C, the α→β phase transition temperature of TA2, which makes the ductility of TA2 fall and the microstructure of the joint coarse. In this paper, Ti-Zr-Cu-Ni amorphous filler was redesigned and optimized by using orthogonal experiment to obtain three easy-to-use Zr-Ti-Ni-Cu amorphous fillers with low melting points and good plasticity. The fast cooling equipment was used to fabricate the brazing filler foils to implement the braze welding of TA2 and Q235 with high frequency inductance. The results indicate that all the brazing foils are amorphous structure with lower melting temperature, for example, Zr52Ti22Ni18Cu8 filler’s is 538°C. The technical parameters in brazing welding are: welding temperature T = 800°C;heating electric current I =25 A;heating time t = 15 s and holding time t = 15 s, in the case of these conditions, the jointing head shear strength of TA2/Zr52Ti24Ni13Cu11/Q235 is 139 MPa. Fracture is mainly located in the brazing seam. The white brittle intermetallic TiFe, TiFe2 and enhancement TiC spread in the center zone of brazing seam.展开更多
WC-Co hard metal was furnace brazed by Ag-Cu-Zn+Ni/Mn filler alloy using a tube furnace under high-purity argon at730°C.The influence of brazing time and gap size of joints was studied.The results revealed the ma...WC-Co hard metal was furnace brazed by Ag-Cu-Zn+Ni/Mn filler alloy using a tube furnace under high-purity argon at730°C.The influence of brazing time and gap size of joints was studied.The results revealed the maximum shear strength of(156±7)MPa for samples with150μm gap size at a holding time15min.The characterization and microstructure of the brazed joints were characterized by SEM,EDS and XRD.The results showed that increasing the time from5to15min could provide a better chance for the liquid interlayer to flow towards the base metal.However,the formation of some metallic phases such as Mn3W3C at brazing time longer than15min resulted in decreased shear strength of the joint.展开更多
We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle...We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle of the Ag-Nb_(2)O_(5)/Al_(2)O_(3) system almost linearly decreases from~71.6°to 32.5°with the Nb_(2)O_(5) content increasing,and the joint shear strength reaches the maximum of~65.1 MPa while employing the Ag-4Nb_(2)O_(5) filler,which are mainly related to the formation and distribution of the AgNbO_(3) phase at the interface.Moreover,the interfacial bonding and electronic properties of related interfaces were investigated by first-principles calculations.The calculated works of adhesion(Wa)of Ag(111)/Ag-O-AgNbO_(3)(001)and AgNbO_(3)(001)/Al_(2)O_(3)(100)interfaces are higher than that of the Ag(111)/Al_(2)O_(3)(110)interface,indicating good reliability of the Ag/AgNbO_(3)/Al_(2)O_(3) structure.The relatively large interfacial charge transfer indicates the formation of Ag-Ag,Al-O,and Ag-O bonds in the Ag/AgNbO_(3)/Al_(2)O_(3) structure,which can contribute to the interfacial bonding.展开更多
采用BNi2钎料,对ZrB2-SiC陶瓷复合材料进行真空钎焊研究.借助SEM,EDS,XRD等分析测试手段分析了界面组织结构及性能.确定了最佳钎焊工艺参数:钎焊温度1160℃,保温时间20 min.结果表明,接头界面产物主要有δ-Ni2Si,β1-Ni3Si,ZrB2+C,Ni(s,...采用BNi2钎料,对ZrB2-SiC陶瓷复合材料进行真空钎焊研究.借助SEM,EDS,XRD等分析测试手段分析了界面组织结构及性能.确定了最佳钎焊工艺参数:钎焊温度1160℃,保温时间20 min.结果表明,接头界面产物主要有δ-Ni2Si,β1-Ni3Si,ZrB2+C,Ni(s,s),Cr x B y C z.随着钎焊温度升高以及保温时间的延长,接头抗剪强度均先升高后降低.钎焊温度1 160℃,保温时间20 min,钎焊接头室温抗剪强度达到最大121.3 MPa.钎焊温度和保温时间对接头断裂方式的影响有相似的规律,在保温时间较短时,裂纹主要产生于钎缝中的Ni(s,s)中,之后向Ni元素扩散层中扩展;当保温时间适中时,断裂主要发生在Ni元素扩散层中;当保温时间延长时,裂纹主要产生于含有一定β1-Ni3Si相的Ni(s,s)中,之后向Ni元素扩散层中扩展.展开更多
The novel Ni-based brazing filler was used to join C/C composites.When brazing temperature increased from 1080 to 1100°C,the wetting angle decreased from 23°to 14°,and the brazing filler had good wettab...The novel Ni-based brazing filler was used to join C/C composites.When brazing temperature increased from 1080 to 1100°C,the wetting angle decreased from 23°to 14°,and the brazing filler had good wettability on the surface of C/C composites.The brazing seam of the brazed joint consisted of Ni(s,s)and Cr_(3)C_(2) phases.As brazing temperature increased,lots of Cr_(3)C_(2) phases were generated at the bonding interface,and the thick reaction layer was formed.When brazing temperature was 1120°C,the shear strength of C/C joint reached the maximum value of 31.5 MPa.The fracture path extended in the C/C matrix close to the bonding interface.展开更多
基金Projects (50975062, 51105107, 51021002) supported by the National Natural Science Foundation of ChinaProjects (QC2011C044) supported by the Natural Science Foundation of Heilongjiang Province,China+1 种基金Project (20112302130005) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject (CUGA4130902510) supported by the China Postdoctoral Science Foundation Funded
文摘Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental observations, the molten interlayer reacts vigorously with base metals, forming several continuous reaction layers. The typical interfacial microstructure of the joint can be expressed as GH99/（Ni,Cr）ss（γ）/TiNi（β2）＋TiNi2Al（τ4）＋Ti2Ni（δ）/δ＋Ti3Al（α2）＋Al3NiTi2（τ3）/α2＋τ3/TiAl. The maximum shear strength is 258 MPa for the specimen brazed at 1000°C for 10 min. Higher brazing temperature or longer brazing time causes coarsening of the phases in the brazing seam and formation of brittle intermetallic layer, which greatly depresses the shear strength of the joints.
基金Project(2010A080402014)supported by the Guangdong Provincial Science and Technology Foundation,China
文摘A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?Ge filler metals drops from 592 to 519 °C as the content of Ge increases from 0 to 30% (mass fraction). As the content of Ge increases, bright eutectic Ge forms. However, as the Ge content exceeds 20%, the aggregation growth of the eutectic structure tends to happen and coarsened primary Si?Ge particle forms, which is detrimental to the properties of alloys. The Al?10.8Si?10Ge filler metal has good processability and wettability with the base metal Al. When this filler metal is used to braze 1060 aluminum, the complete joint can be achieved. Furthermore, the shear strength test results show that the fracture of brazed joint with Al?10.8Si?10Ge filler metal occurs in the base metal.
基金Project(51865012)supported by the National Natural Science Foundation of ChinaProject(20202BABL204040)supported by the Natural Science Foundation of Jiangxi Province,China+3 种基金Project(2016005)supported by the Open Foundation of National Engineering Research Center of Near-net-shape Forming for Metallic Materials,ChinaProject(GJJ170372)supported by the Science Foundation of Educational Department of Jiangxi Province,ChinaProject(JCKY2016603C003)supported by the GF Basic Research Project,ChinaProject(JPPT125GH038)supported by the Research Project of Special Furnishment and Part,China。
文摘The influence of brazing temperature and brazing time on the microstructure and shear strength ofγ-TiAl/GH536 joints brazed with Ti-Zr-Cu-Ni-Fe-Co-Mo filler was investigated using SEM,EDS,XRD and universal testing machine.Results show that all the brazed joints mainly consist of four reaction layers regardless of the brazing temperature and brazing time.The thickness of the brazed seam and the average shear strength of the joint increase firstly and then decrease with brazing temperature in the range of 1090-1170℃and brazing time varying from 0 to 20 min.The maximum shear strength of 262 MPa is obtained at 1150℃for 10 min.The brittle Al3NiTi2 and TiNi3 intermetallics are the main controlling factors for the crack generation and deterioration of joint strength.The fracture surface is characterized as typical cleavage fracture and it mainly consists of massive brittle Al3NiTi2 intermetallics.
文摘In order to research the influence of Zr content （ below 15 wt. % ） on the properties of the filler metal. Ti-5Zr- 15Cu-15Ni-La, Ti-lOZr-15Cu-15Ni-La and Ti-15Zr-15Cu-15Ni-La filler metals were prepared. The wettability of the filler metals on Ti-6Al-4V was evaluated and the melting temperatures of the filler metals were tested by differential scanning calorimetry （DSC）. The microstructures and mechanical properties of the brazed joints were investigated. The results show that the wettability of the filler metals improves as the Zr content increases. Zr content has great influence on the melting temperature of the filler metals. When Zr content changes from 5 wt. % to 10 wt. % and 15 wt. % , the melting temperature decreases about 80 ℃. The brazed joint with Ti-5Zr-15Cu-15Ni-La filler metal shows aciculate phase on the interfizce. The brazed joints with Ti-lOZr-15Cu-15Ni-La and Ti-15Zr-15Cu-15Ni-La filler metals consist of three zones, a segregated center zonc, diffusion reaction zone and acicular zone. The brazed joint with Ti-5Zr-15Cu-15Ni-La filler metal achieves the maximum shear strength 313.9 MPa.
文摘Ti-Zr-Cu-Ni amorphous filler with good performance is suitable for joining TC and TB titanium alloy, but its melting temperature is higher than 882.5°C, the α→β phase transition temperature of TA2, which makes the ductility of TA2 fall and the microstructure of the joint coarse. In this paper, Ti-Zr-Cu-Ni amorphous filler was redesigned and optimized by using orthogonal experiment to obtain three easy-to-use Zr-Ti-Ni-Cu amorphous fillers with low melting points and good plasticity. The fast cooling equipment was used to fabricate the brazing filler foils to implement the braze welding of TA2 and Q235 with high frequency inductance. The results indicate that all the brazing foils are amorphous structure with lower melting temperature, for example, Zr52Ti22Ni18Cu8 filler’s is 538°C. The technical parameters in brazing welding are: welding temperature T = 800°C;heating electric current I =25 A;heating time t = 15 s and holding time t = 15 s, in the case of these conditions, the jointing head shear strength of TA2/Zr52Ti24Ni13Cu11/Q235 is 139 MPa. Fracture is mainly located in the brazing seam. The white brittle intermetallic TiFe, TiFe2 and enhancement TiC spread in the center zone of brazing seam.
文摘WC-Co hard metal was furnace brazed by Ag-Cu-Zn+Ni/Mn filler alloy using a tube furnace under high-purity argon at730°C.The influence of brazing time and gap size of joints was studied.The results revealed the maximum shear strength of(156±7)MPa for samples with150μm gap size at a holding time15min.The characterization and microstructure of the brazed joints were characterized by SEM,EDS and XRD.The results showed that increasing the time from5to15min could provide a better chance for the liquid interlayer to flow towards the base metal.However,the formation of some metallic phases such as Mn3W3C at brazing time longer than15min resulted in decreased shear strength of the joint.
基金supported by National Natural Science Foundation of China(Nos.52002153 and 51572112)Postdoctoral Science Foundation of China(No.2021M701470)+1 种基金Qing Lan Project[(2016)15]of jiangsu ProvinceInnovation/Entrepreneurship Program(No.JSSCTD202146)of Jiangsu Province.
文摘We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle of the Ag-Nb_(2)O_(5)/Al_(2)O_(3) system almost linearly decreases from~71.6°to 32.5°with the Nb_(2)O_(5) content increasing,and the joint shear strength reaches the maximum of~65.1 MPa while employing the Ag-4Nb_(2)O_(5) filler,which are mainly related to the formation and distribution of the AgNbO_(3) phase at the interface.Moreover,the interfacial bonding and electronic properties of related interfaces were investigated by first-principles calculations.The calculated works of adhesion(Wa)of Ag(111)/Ag-O-AgNbO_(3)(001)and AgNbO_(3)(001)/Al_(2)O_(3)(100)interfaces are higher than that of the Ag(111)/Al_(2)O_(3)(110)interface,indicating good reliability of the Ag/AgNbO_(3)/Al_(2)O_(3) structure.The relatively large interfacial charge transfer indicates the formation of Ag-Ag,Al-O,and Ag-O bonds in the Ag/AgNbO_(3)/Al_(2)O_(3) structure,which can contribute to the interfacial bonding.
文摘采用BNi2钎料,对ZrB2-SiC陶瓷复合材料进行真空钎焊研究.借助SEM,EDS,XRD等分析测试手段分析了界面组织结构及性能.确定了最佳钎焊工艺参数:钎焊温度1160℃,保温时间20 min.结果表明,接头界面产物主要有δ-Ni2Si,β1-Ni3Si,ZrB2+C,Ni(s,s),Cr x B y C z.随着钎焊温度升高以及保温时间的延长,接头抗剪强度均先升高后降低.钎焊温度1 160℃,保温时间20 min,钎焊接头室温抗剪强度达到最大121.3 MPa.钎焊温度和保温时间对接头断裂方式的影响有相似的规律,在保温时间较短时,裂纹主要产生于钎缝中的Ni(s,s)中,之后向Ni元素扩散层中扩展;当保温时间适中时,断裂主要发生在Ni元素扩散层中;当保温时间延长时,裂纹主要产生于含有一定β1-Ni3Si相的Ni(s,s)中,之后向Ni元素扩散层中扩展.
基金the financial support from the National Natural Science Foundation of China (Nos. 51675030, 51871010, 52005022)Shanghai Aerospace Scienceand Technology Innovation Fund, China (No. SAST2020-117)。
文摘The novel Ni-based brazing filler was used to join C/C composites.When brazing temperature increased from 1080 to 1100°C,the wetting angle decreased from 23°to 14°,and the brazing filler had good wettability on the surface of C/C composites.The brazing seam of the brazed joint consisted of Ni(s,s)and Cr_(3)C_(2) phases.As brazing temperature increased,lots of Cr_(3)C_(2) phases were generated at the bonding interface,and the thick reaction layer was formed.When brazing temperature was 1120°C,the shear strength of C/C joint reached the maximum value of 31.5 MPa.The fracture path extended in the C/C matrix close to the bonding interface.
