Recently,the presentation of the metal-ceramic composite structure design provides an alternative idea for the improvement of components service performance,while conventional methods for joining metals and ceramics h...Recently,the presentation of the metal-ceramic composite structure design provides an alternative idea for the improvement of components service performance,while conventional methods for joining metals and ceramics have to involve a high heat input.However,due to the low melting point of magnesium alloys,the magnesium alloys-ceramics joining system necessitates a low joining temperature.Ultrasonic vibrations can induce numerous defects in the solid matrix,which can effectively promote atomic diffusion and metallurgical bonding between solid-phase interfaces at low temperatures.Thus,ultrasonic-assisted bonding is a highly promising method for achieving rapid and reliable joining between metals and ceramics without the use of interlayers.In this study,the direct bonding of AZ31B alloy with ZrO_(2) ceramic was successfully achieved at 200℃.A polycrystal spinel MgAl_(2)O_(4) with an average thickness of 55 nm was identified at the AZ31B/ZrO_(2) interface.The average shear strength of joints reached 30.47 MPa.Furthermore,the dynamic recrystallization of AZ31B and the oxygendepletion behavior of ZrO_(2) during the bonding process were characterized to illustrate the contribution of ultrasonic vibration to joint bonding.Consequently,the solid interfacial sono-oxidation reaction is proposed to discuss the bonding mechanism of the joint in detail.展开更多
SiO2–BN ceramic and Ti plate were joined by active brazing in vacuum with Ag–Cu–Ti＋BN composite filler.The effect of BN content,brazing temperature and time on the microstructure and mechanical properties of the b...SiO2–BN ceramic and Ti plate were joined by active brazing in vacuum with Ag–Cu–Ti＋BN composite filler.The effect of BN content,brazing temperature and time on the microstructure and mechanical properties of the brazed joints was investigated.The results showed that a continuous Ti N–Ti B2reaction layer formed adjacent to the SiO2–BN ceramic,whose thickness played a key role in the bonding properties.Four Ti–Cu compound layers,Ti2Cu,Ti3Cu4,Ti Cu2and Ti Cu4,were observed to border Ti substrate due to the strong affinity of Ti and Cu compared with Ag.The central part of the joint was composed of Ag matrix,over which some fine-grains distributed.The added BN particles reacted with Ti in the liquid filler to form fine Ti B whiskers and Ti N particles with low coefficients of thermal expansion（CTE）,leading to the reduction of detrimental residual stress in the joint,and thus improving the joint strength.The maximum shear strength of 31 MPa was obtained when 3 wt%BN was added in the composite filler,which was 158%higher than that brazed with single Ag–Cu–Ti filler metal.The morphology and thickness of the reaction layer adjacent to the parent materials changed correspondingly with the increase of BN content,brazing temperature and holding time.Based on the correlation between the microstructural evolution and brazing parameters,the bonding mechanism of SiO2–BN and Ti was discussed.展开更多
The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal. The formation phase and interface structure of the joints were investigated by electron probe microanalysis (EPMA), s...The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal. The formation phase and interface structure of the joints were investigated by electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the joint strength was tested by shearing method. The results showed: there occurred three new formation phases, Cu(s.s), FeNi and Ag(s.s) in TiC cermet/iron joint. The interface structure was expressed as TiC cermet/Cu(s.s)+FeNi/Ag(s.s)+a little Cu(s.s)+a little FeNi/Cu(s.s)+FeNi/iron, With brazing time increasing, there appeared highest shear strength of the joints, the value of which was up to 252.2MPa when brazing time was 10min.展开更多
基金supported by the Shandong Provincial Natural Science Foundation(ZR2023ME111).
文摘Recently,the presentation of the metal-ceramic composite structure design provides an alternative idea for the improvement of components service performance,while conventional methods for joining metals and ceramics have to involve a high heat input.However,due to the low melting point of magnesium alloys,the magnesium alloys-ceramics joining system necessitates a low joining temperature.Ultrasonic vibrations can induce numerous defects in the solid matrix,which can effectively promote atomic diffusion and metallurgical bonding between solid-phase interfaces at low temperatures.Thus,ultrasonic-assisted bonding is a highly promising method for achieving rapid and reliable joining between metals and ceramics without the use of interlayers.In this study,the direct bonding of AZ31B alloy with ZrO_(2) ceramic was successfully achieved at 200℃.A polycrystal spinel MgAl_(2)O_(4) with an average thickness of 55 nm was identified at the AZ31B/ZrO_(2) interface.The average shear strength of joints reached 30.47 MPa.Furthermore,the dynamic recrystallization of AZ31B and the oxygendepletion behavior of ZrO_(2) during the bonding process were characterized to illustrate the contribution of ultrasonic vibration to joint bonding.Consequently,the solid interfacial sono-oxidation reaction is proposed to discuss the bonding mechanism of the joint in detail.
基金supported by the National Natural Science Foundation of China (No. 51405332)
文摘SiO2–BN ceramic and Ti plate were joined by active brazing in vacuum with Ag–Cu–Ti＋BN composite filler.The effect of BN content,brazing temperature and time on the microstructure and mechanical properties of the brazed joints was investigated.The results showed that a continuous Ti N–Ti B2reaction layer formed adjacent to the SiO2–BN ceramic,whose thickness played a key role in the bonding properties.Four Ti–Cu compound layers,Ti2Cu,Ti3Cu4,Ti Cu2and Ti Cu4,were observed to border Ti substrate due to the strong affinity of Ti and Cu compared with Ag.The central part of the joint was composed of Ag matrix,over which some fine-grains distributed.The added BN particles reacted with Ti in the liquid filler to form fine Ti B whiskers and Ti N particles with low coefficients of thermal expansion（CTE）,leading to the reduction of detrimental residual stress in the joint,and thus improving the joint strength.The maximum shear strength of 31 MPa was obtained when 3 wt%BN was added in the composite filler,which was 158%higher than that brazed with single Ag–Cu–Ti filler metal.The morphology and thickness of the reaction layer adjacent to the parent materials changed correspondingly with the increase of BN content,brazing temperature and holding time.Based on the correlation between the microstructural evolution and brazing parameters,the bonding mechanism of SiO2–BN and Ti was discussed.
基金sponsored by National Natural Science Foundation (No.50175021)National Key Laboratory of Advanced Welding Production Technology of Harbin Institute of Technology,China.
文摘The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal. The formation phase and interface structure of the joints were investigated by electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the joint strength was tested by shearing method. The results showed: there occurred three new formation phases, Cu(s.s), FeNi and Ag(s.s) in TiC cermet/iron joint. The interface structure was expressed as TiC cermet/Cu(s.s)+FeNi/Ag(s.s)+a little Cu(s.s)+a little FeNi/Cu(s.s)+FeNi/iron, With brazing time increasing, there appeared highest shear strength of the joints, the value of which was up to 252.2MPa when brazing time was 10min.
