The thermo-mechanical reliability of IMCs(Ni_(3)Sn_(4),Cu_(3)Sn,Cu_(6)Sn_(5))solder joints and Sn-3.9Ag-0.6Cu solder joints was investigated systematically in 3D chip stacking structure subjected to an accelerated the...The thermo-mechanical reliability of IMCs(Ni_(3)Sn_(4),Cu_(3)Sn,Cu_(6)Sn_(5))solder joints and Sn-3.9Ag-0.6Cu solder joints was investigated systematically in 3D chip stacking structure subjected to an accelerated thermal cyclic loading based on finite element simulation and Taguchi method.Effects of different control factors,including high temperature,low temperature,dwell time of thermal cyclic loading,and different IMCs on the stress-strain response and fatigue life of solder joints were calculated respectively.The results indicate that maximum stress-strain can be found in the second solder joint on the diagonal of IMC solder joints array;for Sn-3.9Ag-0.6Cu solder joints array,the corner solder joints show the obvious maximum stress-strain,these areas are the crack propagated locations.The stress-strain and fatigue life of solder joints is more sensitive to dwell temperature,especially to high temperature;increasing the high temperature,dwell time,or decreasing the low temperature,can reduce the stress-strain and enlarge the fatigue life of solder joints.Finally,the optimal design in the 3D-IC structure has the combination of the Cu_(6)Sn_(5)/Cu_(3)Sn,373 K high temperature,233 K low temperature,and 10 min dwell time.The fatigue lives of Sn-3.9Ag-0.6Cu under 218-398 K loading in the 3D assembly based on the creep strain are 347.4 cycles,which is in good agreement with experimental results(380 cycles).展开更多
Superalloy thin-walled structures are achieved mainly by brazing,but the deformation process of brazed joints is non-uniform,making it a challenging research task.This paper records a thorough investigation of the eff...Superalloy thin-walled structures are achieved mainly by brazing,but the deformation process of brazed joints is non-uniform,making it a challenging research task.This paper records a thorough investigation of the effect of brazing parameters on the microstructure of joints and its mechanical properties,which mainly inquires into the deformation and fracture mechanisms in the shearing process of GH99/BNi-5a/GH99 joints.The macroscopic-microscopic deformation mechanism of the brazing interface during shearing was studied by Crystal Plasticity(CP)and Molecular Dynamics(MD)on the basis of the optimal brazing parameters.The experimental results show that the brazing interface is mainly formed by(Ni,Cr,Co)(s,s)and possesses a shear strength of approximately 546 MPa.The shearing fracture of the brazed joint occurs along the brazing seam,displaying the characteristics of intergranular fracture.MD simulations show that dislocations disassociate and transform into fine twinning with increased strain.CP simulated the shear deformation process of the brazed joint.The multiscale simulation results are consistent with the experimental results.The mechanical properties of thin-walled materials for brazing are predicted using MD and CP methods.展开更多
Reliable Si C/Sn-Ti/Si C joints were obtained by brazing(950?C/10 min)and soldering(250?C/2 min)following premetallization depend on the wettability of Sn-Ti on Si C.The microstructures of Sn-Ti/Si C interface were ch...Reliable Si C/Sn-Ti/Si C joints were obtained by brazing(950?C/10 min)and soldering(250?C/2 min)following premetallization depend on the wettability of Sn-Ti on Si C.The microstructures of Sn-Ti/Si C interface were characterized by scanning electron microscopy,X-ray diffraction and transmission electron microscopy,and the mechanical properties of joints were evaluated by shear tests.Active Ti enhanced the wettability of Sn on Si C with the decrease of contact angle from 150?to 20?.Ti direct reacted with Si C to produce Ti C and combines with released Si forming Ti5Si3.Much lower Ti concentration per contacting area in brazing and metallization,compared to wetting,resulted in defective bonding of Sn-Ti/Si C and few amounts of interfacial products(thin Ti C layer or partial covered Ti C layer with Ti5Si3).All of the Si C/Si C joints possess a similar shear strength of 27–32 MPa and rupture through?-Sn matrix in ductile fracture.展开更多
基金Supported by State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology(Grant No.AWJ-19Z04)Major State Research Development Program of China(Grant No.2019YFF0217400)the Central Plains Science and Technology Innovation Leading Talents Program(Grant No.ZYQR20180030).
文摘The thermo-mechanical reliability of IMCs(Ni_(3)Sn_(4),Cu_(3)Sn,Cu_(6)Sn_(5))solder joints and Sn-3.9Ag-0.6Cu solder joints was investigated systematically in 3D chip stacking structure subjected to an accelerated thermal cyclic loading based on finite element simulation and Taguchi method.Effects of different control factors,including high temperature,low temperature,dwell time of thermal cyclic loading,and different IMCs on the stress-strain response and fatigue life of solder joints were calculated respectively.The results indicate that maximum stress-strain can be found in the second solder joint on the diagonal of IMC solder joints array;for Sn-3.9Ag-0.6Cu solder joints array,the corner solder joints show the obvious maximum stress-strain,these areas are the crack propagated locations.The stress-strain and fatigue life of solder joints is more sensitive to dwell temperature,especially to high temperature;increasing the high temperature,dwell time,or decreasing the low temperature,can reduce the stress-strain and enlarge the fatigue life of solder joints.Finally,the optimal design in the 3D-IC structure has the combination of the Cu_(6)Sn_(5)/Cu_(3)Sn,373 K high temperature,233 K low temperature,and 10 min dwell time.The fatigue lives of Sn-3.9Ag-0.6Cu under 218-398 K loading in the 3D assembly based on the creep strain are 347.4 cycles,which is in good agreement with experimental results(380 cycles).
基金support from the National Natural Science Foundation of China(Grant Nos.52175307)the Taishan Scholars Foundation of Shandong Province(No.tsqn201812128)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2023JQ021No.ZR2020QE175).
文摘Superalloy thin-walled structures are achieved mainly by brazing,but the deformation process of brazed joints is non-uniform,making it a challenging research task.This paper records a thorough investigation of the effect of brazing parameters on the microstructure of joints and its mechanical properties,which mainly inquires into the deformation and fracture mechanisms in the shearing process of GH99/BNi-5a/GH99 joints.The macroscopic-microscopic deformation mechanism of the brazing interface during shearing was studied by Crystal Plasticity(CP)and Molecular Dynamics(MD)on the basis of the optimal brazing parameters.The experimental results show that the brazing interface is mainly formed by(Ni,Cr,Co)(s,s)and possesses a shear strength of approximately 546 MPa.The shearing fracture of the brazed joint occurs along the brazing seam,displaying the characteristics of intergranular fracture.MD simulations show that dislocations disassociate and transform into fine twinning with increased strain.CP simulated the shear deformation process of the brazed joint.The multiscale simulation results are consistent with the experimental results.The mechanical properties of thin-walled materials for brazing are predicted using MD and CP methods.
基金supported financially by the National Natural Science Foundation of China(Nos.51775138,U1737205and U1537206)the Key Research&Development Program of Shandong Province(No.2017GGX40103).
文摘Reliable Si C/Sn-Ti/Si C joints were obtained by brazing(950?C/10 min)and soldering(250?C/2 min)following premetallization depend on the wettability of Sn-Ti on Si C.The microstructures of Sn-Ti/Si C interface were characterized by scanning electron microscopy,X-ray diffraction and transmission electron microscopy,and the mechanical properties of joints were evaluated by shear tests.Active Ti enhanced the wettability of Sn on Si C with the decrease of contact angle from 150?to 20?.Ti direct reacted with Si C to produce Ti C and combines with released Si forming Ti5Si3.Much lower Ti concentration per contacting area in brazing and metallization,compared to wetting,resulted in defective bonding of Sn-Ti/Si C and few amounts of interfacial products(thin Ti C layer or partial covered Ti C layer with Ti5Si3).All of the Si C/Si C joints possess a similar shear strength of 27–32 MPa and rupture through?-Sn matrix in ductile fracture.
