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Characterization and degradation of β-Sn particles in thermal aged Pb-rich solder joint for low-temperature co-fired ceramic(LTCC) applications

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Rare Metals 2024年第10期43卷 5346-5361页

作者： Jin-Hong Liu Zhe Zhu Qiang-Qiang Nie Jun-Fu Liu Peng He Shu-Ye Zhang state key laboratory of advanced welding and joining Harbin Institute of Technology Anhui key laboratory of Microsystem East China Research Institute of Microelectronics School of Materials Science and Engineering Hefei University of Technology

High-lead solder joints are still playing an indispensable role in military and space ***, in-depth characterization of high-lead solder joints and the underlying degradation mechanisms remain unexplored. This research first performed aging tests on Sn10Pb90 solder joints, the shear strength at room and elevated temperatures gradually reduced, and the resistance increased. Here, a two-layered Ni–Sn intermetallic compound(IMC) structure was identified using transmission electron microscopy(TEM), which could be attributed to the change of Sn content in the solder. Moreover, the internal annealing twin of a Sn particle was discovered,which could be attributed to creeping induced by thermal expansion coefficient(CTE) difference between Sn and *** analysis of partial and whole annealing twins was conducted through high-resolution TEM(HRTEM).Finally, four degradation mechanisms were *** of the IMC layer would result in increased brittleness and resistivity. For particle coarsening, apart from diminishing the ductility and toughness of the solder joint, it would also accelerate the creeping rate by weakening the phase boundary strength. Regarding voids and cracks induced by phase boundary sliding, wedgeshaped cracking and pore-shaped cracking were discovered and their formation was analyzed. Most importantly, the consumption of Sn resulted in a depletion of wettable layer,leading to the formation of Pb streams and isolated IMC islands, also known as the spalling and delamination of IMCs. Pb diffusion followed a spiral path, which was mutually influenced by orientation misfit and concentration gradient. A technique to prevent cracking was *** research is expected to provide significant technical references for high-lead solder joints.

关键词： Aging Degradation mechanisms High-lead solder joints Properties TEM characterization

A novel seal-flow multi-vortex friction stir lap welding of metal to polymer matrix composites

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Chinese Journal of Aeronautics 2024年第1期37卷 451-462页

作者： Shuaiqiang NIAN Mingshen LI Shude JI Wei HU Zhiqing ZHANG Zelin SUN College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin 150001China

The friction stir lap welding(FSLW)of metal to polymer is a challenging work due to the unavoidable polymer *** this problem,a novel seal-flow multi-vortex friction stir lap welding(SM-FSLW)technology based on the subversively-designed multi-step pin was put *** 7075 aluminum alloy and short glass fiber-reinforced polyether ether ketone(PEEK)as research subjects,the welding temperature,material flow,formation and tensile shear strength of dissimilar materials lap joint under the SM-FSLW were studied and compared with those under traditional FSLW based on the conical *** multi-step pin rather than the conical pin effectively hindered the polymer overflowing due to the formation of vortexes by the step,thereby attaining a joint with a smooth *** with traditional FSLW,the SMFSLW obtained the higher welding temperature,the more violent material flow and the larger area with high flow velocity,thereby producing the macro-mechanical and micro-mechanical interlockings and then heightening the joint loading *** tensile shear strength of lap joint under SM-FSLW was 27.8% higher than that under traditional *** SM-FSLW technology using the multi-step pin provides an effective way on obtaining a heterogeneous lap joint of metal to polymer with the excellent formation and high strength.

关键词： Friction stir lap welding Metal to polymer Multi-step pin Material flow Tensile shear strength

Microstructure,mechanical and fracture properties of friction stir welded 2195 Al-Li alloy joints

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Chinese Journal of Aeronautics 2024年第1期37卷 345-361页

作者： Guangda SUN Weizhao SUN Li ZHOU Sanfeng LUO Zili ZHANG Debo LIU Huiqiang WU state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial key laboratory of Special welding Technology Harbin Institute of Technology(Weihai)Weihai 264209China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

The 8 mm-thick 2195 Al-Li alloy joints were achieved by Friction Stir welding(FSW).The microstructural evolution,temperature-dependent mechanical properties,and fracture properties were *** T1,δ’/β’and θ’precipitates were observed in the Base Metal(BM)and the Heat Affected Zone(HAZ).Most of the precipitates,except for re-precipitated δ’/β’phases,were dissolved in the Nugget Zone(NZ).The tensile specimens that failed at cryogenic temperatures(-196℃)had the maximum Ultimate Tensile Strength(UTS),and the fracture surface showed the inter-granular fracture *** to those at room temperature(25℃),the decreasing tensile properties at high temperature(180℃)were related to microstructure and strain hardening *** NZ presented the optimal fracture toughness,and the Crack Tip Opening Displacement(CTOD)was mutually dominated by microhardness and grain *** on Fatigue Crack Growth(FCG)rates indicates that the Thermal-Mechanically Affected Zone(TMAZ)exhibited the most superior fatigue resistance performance at stress intensity range below17 MPa.m1/2due to compressive residual stress and the crack closure *** fatigue fracture surfaces reveal that the crack propagation zone was characterized by the striations and secondary ***,inter-granular fracture behavior was responsible for the fastest FCG rates in the NZ.

关键词： Aluminum alloys Friction stir welding Microstructural evolution Mechanical properties Fracture mechanism

Design and fabrication of lightweight AlCrFeNiTi_(x) compositionally complex alloys with exceptional specific strength

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Rare Metals 2024年第7期43卷 3314-3328页

作者： Jun-Zhi Li Wei-Zong Bao Jie chen Bo-Hua Yu Kun Zuo Tian Gao Ze-Yun Cai Guo-Qiang Xie School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin 150001China

This study focuses on compositionally complex alloys(CCAs),aiming to achieve a balance between high strength and low density for new energy and aerospace *** composition of AlCrFeNiTi_(x) CCAs is strategically guided by employing density functional theory and the theoretical design of thermodynamic *** CCAs,particularly AlCrFeNiTi_(0.25) alloy,demonstrate remarkable specific yield strength(1640.8 MPa) and 22.7% maximum *** incorporation of Ti facilitates the formation of lightweight and high-strength L2_(1)phase,contributing to the overall high specific *** effects of grain boundary strengthening,solid solution strengthening,Orowan strengthening and Peierls flow stress further enhance *** exploration of micros tructural changes during fracture reveals the role of ordered phases in suppressing crack propagation and absorbing energy within disordered phases,thereby improving the toughness and fracture resistance of *** methods and discoveries establish a robust foundation for advancing the development of novel lightweight CCAs.

关键词： Lightweight Compositionally complex alloys Specific yield strength

In-situ isothermal aging TEM analysis of a micro Cu/ENIG/Sn solder joint for flexible interconnects

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Journal of Materials Science & Technology 2024年第2期169卷 42-52页

作者： Jinhong Liu Jianhao Xu Kyung-Wook Paik Peng He Shuye Zhang state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin150001China Department of materials science and engineering KAIST291 Daehak-roYuseong-guDaejeon305-338Republic of Korea

Sn/ENIG has recently been used in flexible interconnects to form a more stable micron-sized metallurgical joint,due to high power capability which causes solder joints to heat up to 200℃.However,Cu_(6)Sn_(5)which is critical for a microelectronic interconnection,will go through a phase transition at temperatures between 186 and 189℃.This research conducted an in-situ TEM study of a micro Cu/ENIG/Sn solder joint under isothermal aging test and proposed a model to illustrate the mechanism of the microstructural *** results showed that part of the Sn solder reacted with Cu diffused from the electrode to formη´-Cu_(6)Sn_(5)during the ultrasonic bonding process,while the rest of Sn was left and enriched in a region in the solder *** the enriched Sn quickly diffused to both sides when the temperature reached 100℃,reacting with the ENIG coating and Cu to form(Ni_(x)Cu_(1-x))_(3)Sn_(4),AuSn_(4),and Cu_(6)Sn_(5)*** entering the heat preservation process,the diffusion of Cu from the electrode to the joint became more intense,resulting in the formation of Cu_(3)*** scallop-type Cu_(6)Sn_(5)and the seahorse-type Cu_(3)Sn constituted a typical two-layered structure in the solder *** importantly,the transition betweenηandη’was captured near the phase transition temperature for Cu_(6)Sn_(5)during both the heating and cooling process,which was accompanied by a volume shifting,and the transition process was further *** research is expected to serve as a reference for the service of micro Cu/ENIG/Sn solder joints in the electronic industry.

关键词： In-situ TEM observation Isothermal aging Micro Cu/ENIG/Sn solder joint Cu_(6)Sn_(5)phase transition

Multi-scale analyses of phase transformation mechanisms and hardness in linear friction welded Ti17(a+β)/Ti17(β)dissimilar titanium alloy joint

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Chinese Journal of Aeronautics 2024年第1期37卷 312-324页

作者： Zhenguo GUO Tiejun MA Xiawei YANG Ju LI Wenya LI Achilles VAIRIS state key laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China Aeronautical key laboratory for welding and joining Technologies AVIC Manufacturing Technology InstituteBeijing 100024China Mechanical Engineering Department University of West AtticaAthens 12241Greece

The Ti17(a+β)-Ti17(β)dual alloy-dual property blisk produced using Linear Friction welding(LFW)is considered as high-performance component in advanced ***,up to now,microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(a+β)/Ti17(β)dissimilar joint have not been thoroughly *** this work,complex analyses of the phase transformation mechanisms of the joint are conducted,and phase transformations in individual zones are correlated to their microhardness and *** reveal that a dissolution occurs under high temperatures encountered during LFW,which reduces microhardness of the joint to that of Ti17(a+β)and Ti17(β).In ThermoMechanically Affected Zone of Ti17(a+β)(TMAZ-(a+β))side joint,a large number of nanocrystalline a phases form with different *** microstructure strengthens significantly by fine grains which balances partial softening effect of a dissolution,and increases nanohardness of a phase and microhardness of TMAZ-(a+β).Superlattice metastableβphase precipitates from metastableβin Weld Zone(WZ)during quick cooling following welding,because of short-range diffusion migration of solute atoms,especiallyβstabilizing elements Mo and *** precipitation of the superlattice metastableβphase results in precipitation strengthening,which in turn increases nanohardness of metastableβand microhardness in WZ.

关键词： Linear friction welding Ti17 titanium alloy Phase transformation Microhardness Nanohardness

Hot deformation behavior and microstructure evolution of GH3536-TiB_(2) composites fabricated by powder metallurgy

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Science China(Technological Sciences) 2024年第7期67卷 2107-2124页

作者： ZHOU ShiPeng WANG Shuai HUANG LuJun ZHANG Rui chen Xin MENG FanChao chen Run SUN FengBo WANG CunYu GENG Lin School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin 150001China

The hot deformation behavior and microstructure evolution of GH3536-TiB2composites fabricated by powder metallurgy(PM)were examined in the temperature range of 950–1150℃ and strain rate range of 0.001–1 s^(-1). The hot compression stress-strain curves and the constitutive equation were obtained. In addition, the hot processing map was drawn, which indicated that the appropriate hot working window was 950–1050℃/0.001–0.1 s^(-1)and 1050–1100℃/0.001–0.01 s^(-1). The microstructure analysis showed that the splitting and spheroidization of M3B2led to a decrease in size and volume fraction at 950–1100℃. At 1150℃,the eutectic microstructure of M_(3)B_(2)+ γ was formed due to the dissolution of M_(3)B_(2), which caused macroscopic cracking of the deformed sample. Additionally, the deformation temperature and the strain rate had little effect on the size and volume fraction of M_(3)B_(2). Besides, discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX) were found in the deformed microstructure, while the former was dominant. Within the test range of this work, the dynamic recrystallization(DRX) fraction of the deformed composites was high due to the bulging nucleation of numerous interfaces. The DRX grain size increased with increasing deformation temperature or decreasing strain rate. Texture analysis showed that the deformation texture of //compression direction RD existed in the matrix when the deformation temperature was below 1100℃, and the texture type became //RD at 1100℃. Additionally, it was also found that the //RD texture was formed in M3B2under the strain rates of 0.1 and 0.01 s^(-1).

关键词： GH3536 alloy matrix composites powder metallurgy hot deformation behavior microstructure evolution

Fatigue Crack Initiation and Propagation Dominated by Crystallographic Factors in TiB/near α-Ti Composite

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 763-776页

作者： Fanchao Meng Rui Zhang Shuai Wang Fengbo Sun Run chen Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbin 150001China

Discontinuously reinforced titanium matrix composites(DRTMCs)with a network structure have been extensively researched due to their superior combination of strength and ***,their fatigue performance has remained *** order to elucidate the fatigue behavior of DRTMCs,a tension-tension fatigue test was performed on a TiB/nearα-Ti composite with network *** results showed that the variability of fatigue lifetime increased as the stress level *** analysis indicated that fatigue crack initiation was associated with facet formation,while the subsequent propagation was hindered by the network structure comprising TiB whiskers and *** characterization further revealed that facets formed due to a combination of shear and normal *** reduction in fatigue lifetime was attributed to an increase in the effective slip length,which was influenced by the orientation of grains near the crack-initiation sites toward basal slip in the life-limiting *** in situ observation suggested that the crack initiation was facilitated by both basal and prismatic slip ofα-Ti as well as fracture of *** propagation was found to be associated with basal and prismatic slip systems with high Schmid factors,regardless of whether the crack was intergranular or intragranular.

关键词： Titanium matrix composite TiBw Fatigue lifetime variability Crack initiation Crack propagation

Liquid metal as an efficient protective layer for lithium metal anodes in all-solid-state batteries

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Carbon Energy 2024年第7期6卷 219-229页

作者： Shiqiang Zhou Mengrui Li Peike Wang Lukuan cheng Lina chen Yan Huang Boxuan Cao Suzhu Yu Qingju Liu Jun Wei Shenzhen key laboratory of Flexible Printed Electronics Technology Harbin Institute of TechnologyShenzhenChina School of Materials Science and Engineering Harbin Institute of TechnologyShenzhenChina state key laboratory of advanced welding and joining Harbin Institute of TechnologyHarbinChina Yunnan key laboratory for Micro/Nano Materials and Technology School of Materials and EnergyYunnan UniversityKunmingChina

Lithium metal batteries with inorganic solid-state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high-energy content and ***,inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial ***,we report a liquid metal-coated lithium metal(LM@Li)anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic *** LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2mA cm^(-2) and a significantly higher critical current density of 9.8 mAcm^(-2) at 25°*** addition,a full battery assembled with a high-capacity composite LiNbO3@-LiNi_(0.7)Co_(0.2)Mn_(0.1)O_(2)(LNO@NCM721)cathode shows stable cycling *** and computational results have demonstrated that dendrite growth tolerance and physical contact in solid-state batteries can be reinforced by using LM interlayers for interfacial modification.

关键词： all-solid-state batteries interface engineering liquid metals lithium metal anodes