Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joi...Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joint performance of Mg/Al.In this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)filler.The effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically investigated.The Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al joints.The blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating layer.The content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength decreased.The joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 MPa.By pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength increased.However,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the solder.Transmission electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC interface.Pre-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.展开更多
The plastic deformation of solder joint depends on the plastic deformation resistance of solder. The studyon plastic deformation resistance of Sn-Pb-RE solder at room temperature shows that with the increase 0f RE con...The plastic deformation of solder joint depends on the plastic deformation resistance of solder. The studyon plastic deformation resistance of Sn-Pb-RE solder at room temperature shows that with the increase 0f RE content, theplastic deformation resistance of Sn-Pb-RE solder enhances. The microstructure investigation reveals'that the addition ofRE makes the microstructure of solder fine and homogeneous, which enhances hwher hardening and multi-sliding hardening. Moreover, RE on grain boundaries hinders the grain boundary sliding. Therefore, the deformation resistance ofsolder enhances. However, since it is very hard, the intermetallic compounds of RE near fracture surface will cause intergranular cracks around it.展开更多
SiC nanoparticles reinforced eutectic Sn-Pb solder were prepared by mechanical mixing method. Reactive wetting of the resultant composite solders on Cu substrates was investigated using real time, in-situ visualizatio...SiC nanoparticles reinforced eutectic Sn-Pb solder were prepared by mechanical mixing method. Reactive wetting of the resultant composite solders on Cu substrates was investigated using real time, in-situ visualization of the triple-line movement. It was found that spreading rates of all solder pastes in this work do not obey Tanner' s law of non-reactive spreading. SiC nano-particles slow down both the pre-melting and post-melting spreading rates of composite solder pustes. As the content of SiC nano-particles increase, the melting point of composite solders decrease, and the spreading time of molten composite solder pastes increases.展开更多
Specimens of Sn-Pb-0.05RE solder alloy were tested to failure under two different stress states,uniaxial tension using smooth bar specimens and triaxial tension using notched bar specimens. The tests were conducted at...Specimens of Sn-Pb-0.05RE solder alloy were tested to failure under two different stress states,uniaxial tension using smooth bar specimens and triaxial tension using notched bar specimens. The tests were conducted at a temperature of 125℃, far above 0. 5 melting temperature of Sn-Pb-0.05RE solder alloy,which leads to a distinctive creep deformation. Rupture times were compared for uniaxial and triaxial stress states with respect to multiaxial stress parameters that are directly related to physical fracture mechanisms.The success of the parameters was judged according to how well the stress parameters correlate with the time to rupture. The results show that the Mises effective stress is the stress factor which dominates the creep rupture of Sn-Pb-0. 05RE solder alloy. It further suggests that the cavity nucleation on a grain boundary plays an important role in the creep rupture process of Sn-Pb-0.05RE solder alloy.展开更多
The purpose of this paper is to investigate the effect of 2 wt%Ag addition in Sn-Pb eutectic solder on microstructure and mechanical properties of AgCu/solder/CuBe joint fabricated by vapor phase soldering.63Sn37Pb an...The purpose of this paper is to investigate the effect of 2 wt%Ag addition in Sn-Pb eutectic solder on microstructure and mechanical properties of AgCu/solder/CuBe joint fabricated by vapor phase soldering.63Sn37Pb and 62Sn36Pb2Ag solder pastes were used to join Cu(1.7 wt%-2.5 wt%)Be and Ag(2 wt%-5 wt%)Cu alloys.Two fracture modes are observed in 62Sn36Pb2Ag and 63Sn37Pb joints after lateral shear tests at room temperature or 120℃,and shear forces of 62Sn36Pb2Ag joints are far higher than those of 63Sn37Pb joints.No obvious difference is observed in morphology and thickness of intermetallic compounds(IMCs)at interfaces of the 63Sn37Pb and 62Sn36Pb2Ag joints.Within the two kinds of joints,for-mation of big blocky or plate-like Ag_(3)Sn is restrained.However,many Ag_(3)Sn IMCs particles(1-3 μm in width)in isolated and dispersed distribution are observed within 62Sn36Pb2Ag joints.The Ag3Sn particles are responsible for the better mechanical properties of 62Sn36Pb2 Ag joints than those of 63Sn37Pb joints.The results present in this paper may provide a guide for restraining formation of big blocky or plate-like Ag_(3) Sn in joints with Ag pads or thick Ag surface finish on pads by utilizing vapor phase soldering process,and improving mechanical properties of Cu/SnPb/Ag joints by adding Ag in SnPb eutectic solder.展开更多
In recent years,the rapid development of the new energy industry has driven continuous upgrading of high-density and high-power devices.In the packaging and assembly process,the problem of differentiation of the therm...In recent years,the rapid development of the new energy industry has driven continuous upgrading of high-density and high-power devices.In the packaging and assembly process,the problem of differentiation of the thermal needs of different modules has become increasingly prominent,especially for small-size solder joints with high heat dissipation in high-power devices.Localized soldering is con-sidered a suitable choice to selectively heat the desired target while not affecting other heat-sensitive chips.This paper reviews several local-ized soldering processes,focusing on the size of solder joints,soldering materials,and current state of the technique.Each localized solder-ing process was discovered to have unique characteristics.The requirements for small-size solder joints are met by laser soldering,microres-istance soldering,and self-propagating soldering;however,laser soldering has difficulty meeting the requirements for large heat dissipation,microresistance soldering requires the application of pressure to joints,and self-propagating soldering requires ignition materials.However,for small-size solder junctions,selective wave soldering,microwave soldering,and ultrasonic soldering are not appropriate.Because the magnetic field can be focused on a tiny area and the output energy of induction heating is large,induction soldering can be employed as a significant trend in future research.展开更多
Active soldering of 5A06 Al alloy was performed at 300 ℃ by using Sn-1Ti and Sn-1Ti-0.3Ga active solders, respectively. Theeffects of soldering time on the microstructure and mechanical properties of the joints were ...Active soldering of 5A06 Al alloy was performed at 300 ℃ by using Sn-1Ti and Sn-1Ti-0.3Ga active solders, respectively. Theeffects of soldering time on the microstructure and mechanical properties of the joints were investigated. The results showed that the Sn-1Tisolder broke the oxide film on the surface of the Al substrate and induced intergranular diffusion in the Al substrate. When Ga was added tothe solder, severe dissolution pits appeared in the Al substrate due to the action of Sn-1Ti-0.3Ga solder, and many Al particles were flakedfrom the matrix into the solder seam. Under thermal stress and the Ti adsorption effect, the oxide film cracked. With increasing solderingtime, the shear strength of 5A06 Al alloy joints soldered with Sn-1Ti and Sn-1Ti-0.3Ga active solders increased. When soldered for 90 min,the joint soldered with Sn-1Ti-0.3Ga solder had a higher shear strength of 22.12 MPa when compared to Sn-1Ti solder.展开更多
The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned ab...The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned above.Harsh environments will lead to solder joints degradation or even failure,resulting in damage to onboard electronics.The research activities on high reliability solder joints using in extreme environments can not only reduce the use of onboard protection devices,but effectively improve the overall reliability of spacecraft,which is of great significance to the aviation industry.In this paper,we review the reliability research on SnPb solder alloys,Sn-based lead-free solder alloys and In-based solder alloys in extreme environments,and try to provide some suggestions for the follow-up studies,which focus on solder joint reliability under extreme environments.展开更多
The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carrie...The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carried out at room temperature at the strain rate of 4.17 × 10<sup>-3</sup> s<sup>-1</sup>, 20.85 × 10<sup>-3</sup> s<sup>-1</sup>, and 208.5 × 10<sup>-3</sup> s<sup>-1</sup>. It is seen that the tensile strength increases and the ductility decrease with increasing the strain rate over the investigated range. From the strain rate change test results, the strain sensitivity values are found in the range of 0.0831 to 0.1455 due to the addition of different alloying elements.展开更多
基金financial support from the National Natural Science Foundation of China(grant numbers 52275385 and U2167216)the Sichuan Province Science and Technology Support Program(grant number 2022YFG0086)。
文摘Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joint performance of Mg/Al.In this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)filler.The effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically investigated.The Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al joints.The blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating layer.The content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength decreased.The joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 MPa.By pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength increased.However,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the solder.Transmission electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC interface.Pre-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.
文摘The plastic deformation of solder joint depends on the plastic deformation resistance of solder. The studyon plastic deformation resistance of Sn-Pb-RE solder at room temperature shows that with the increase 0f RE content, theplastic deformation resistance of Sn-Pb-RE solder enhances. The microstructure investigation reveals'that the addition ofRE makes the microstructure of solder fine and homogeneous, which enhances hwher hardening and multi-sliding hardening. Moreover, RE on grain boundaries hinders the grain boundary sliding. Therefore, the deformation resistance ofsolder enhances. However, since it is very hard, the intermetallic compounds of RE near fracture surface will cause intergranular cracks around it.
文摘SiC nanoparticles reinforced eutectic Sn-Pb solder were prepared by mechanical mixing method. Reactive wetting of the resultant composite solders on Cu substrates was investigated using real time, in-situ visualization of the triple-line movement. It was found that spreading rates of all solder pastes in this work do not obey Tanner' s law of non-reactive spreading. SiC nano-particles slow down both the pre-melting and post-melting spreading rates of composite solder pustes. As the content of SiC nano-particles increase, the melting point of composite solders decrease, and the spreading time of molten composite solder pastes increases.
文摘Specimens of Sn-Pb-0.05RE solder alloy were tested to failure under two different stress states,uniaxial tension using smooth bar specimens and triaxial tension using notched bar specimens. The tests were conducted at a temperature of 125℃, far above 0. 5 melting temperature of Sn-Pb-0.05RE solder alloy,which leads to a distinctive creep deformation. Rupture times were compared for uniaxial and triaxial stress states with respect to multiaxial stress parameters that are directly related to physical fracture mechanisms.The success of the parameters was judged according to how well the stress parameters correlate with the time to rupture. The results show that the Mises effective stress is the stress factor which dominates the creep rupture of Sn-Pb-0. 05RE solder alloy. It further suggests that the cavity nucleation on a grain boundary plays an important role in the creep rupture process of Sn-Pb-0.05RE solder alloy.
基金financially supported by the National Natural Science Foundation of China (No.51375003)
文摘The purpose of this paper is to investigate the effect of 2 wt%Ag addition in Sn-Pb eutectic solder on microstructure and mechanical properties of AgCu/solder/CuBe joint fabricated by vapor phase soldering.63Sn37Pb and 62Sn36Pb2Ag solder pastes were used to join Cu(1.7 wt%-2.5 wt%)Be and Ag(2 wt%-5 wt%)Cu alloys.Two fracture modes are observed in 62Sn36Pb2Ag and 63Sn37Pb joints after lateral shear tests at room temperature or 120℃,and shear forces of 62Sn36Pb2Ag joints are far higher than those of 63Sn37Pb joints.No obvious difference is observed in morphology and thickness of intermetallic compounds(IMCs)at interfaces of the 63Sn37Pb and 62Sn36Pb2Ag joints.Within the two kinds of joints,for-mation of big blocky or plate-like Ag_(3)Sn is restrained.However,many Ag_(3)Sn IMCs particles(1-3 μm in width)in isolated and dispersed distribution are observed within 62Sn36Pb2Ag joints.The Ag3Sn particles are responsible for the better mechanical properties of 62Sn36Pb2 Ag joints than those of 63Sn37Pb joints.The results present in this paper may provide a guide for restraining formation of big blocky or plate-like Ag_(3) Sn in joints with Ag pads or thick Ag surface finish on pads by utilizing vapor phase soldering process,and improving mechanical properties of Cu/SnPb/Ag joints by adding Ag in SnPb eutectic solder.
基金The research was supported by the National Natural Science Foundation of China(Grant No.52105331)the Shenzhen Science and Technology Innovation Committee(Grant No.JSGG20201102154600003,GXWD20220818163456002,JCYJ20210324124203009).
文摘In recent years,the rapid development of the new energy industry has driven continuous upgrading of high-density and high-power devices.In the packaging and assembly process,the problem of differentiation of the thermal needs of different modules has become increasingly prominent,especially for small-size solder joints with high heat dissipation in high-power devices.Localized soldering is con-sidered a suitable choice to selectively heat the desired target while not affecting other heat-sensitive chips.This paper reviews several local-ized soldering processes,focusing on the size of solder joints,soldering materials,and current state of the technique.Each localized solder-ing process was discovered to have unique characteristics.The requirements for small-size solder joints are met by laser soldering,microres-istance soldering,and self-propagating soldering;however,laser soldering has difficulty meeting the requirements for large heat dissipation,microresistance soldering requires the application of pressure to joints,and self-propagating soldering requires ignition materials.However,for small-size solder junctions,selective wave soldering,microwave soldering,and ultrasonic soldering are not appropriate.Because the magnetic field can be focused on a tiny area and the output energy of induction heating is large,induction soldering can be employed as a significant trend in future research.
基金the National Natural Science Foundation of China(No.52171045).
文摘Active soldering of 5A06 Al alloy was performed at 300 ℃ by using Sn-1Ti and Sn-1Ti-0.3Ga active solders, respectively. Theeffects of soldering time on the microstructure and mechanical properties of the joints were investigated. The results showed that the Sn-1Tisolder broke the oxide film on the surface of the Al substrate and induced intergranular diffusion in the Al substrate. When Ga was added tothe solder, severe dissolution pits appeared in the Al substrate due to the action of Sn-1Ti-0.3Ga solder, and many Al particles were flakedfrom the matrix into the solder seam. Under thermal stress and the Ti adsorption effect, the oxide film cracked. With increasing solderingtime, the shear strength of 5A06 Al alloy joints soldered with Sn-1Ti and Sn-1Ti-0.3Ga active solders increased. When soldered for 90 min,the joint soldered with Sn-1Ti-0.3Ga solder had a higher shear strength of 22.12 MPa when compared to Sn-1Ti solder.
基金Supported by National Natural Science Foundation of China (Grant No.51775141)Heilongjiang Touyan Innovation Team Program。
文摘The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned above.Harsh environments will lead to solder joints degradation or even failure,resulting in damage to onboard electronics.The research activities on high reliability solder joints using in extreme environments can not only reduce the use of onboard protection devices,but effectively improve the overall reliability of spacecraft,which is of great significance to the aviation industry.In this paper,we review the reliability research on SnPb solder alloys,Sn-based lead-free solder alloys and In-based solder alloys in extreme environments,and try to provide some suggestions for the follow-up studies,which focus on solder joint reliability under extreme environments.
文摘The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carried out at room temperature at the strain rate of 4.17 × 10<sup>-3</sup> s<sup>-1</sup>, 20.85 × 10<sup>-3</sup> s<sup>-1</sup>, and 208.5 × 10<sup>-3</sup> s<sup>-1</sup>. It is seen that the tensile strength increases and the ductility decrease with increasing the strain rate over the investigated range. From the strain rate change test results, the strain sensitivity values are found in the range of 0.0831 to 0.1455 due to the addition of different alloying elements.