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Refilled friction stir spot welding of dissimilar Q235 low-carbon steel/5052 aluminum with equal thickness

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钢铁研究学报（英文版） 2024年第10期31卷 2520-2529页

作者： jian-yu Li jia-xu shi Shu-hai Chen ji-hua huang Shu-jun Chen School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China The College of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing 100124China

The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot *** effects of rotation speed and pressure speed on weld forming,tensile strength,and welded joint structure were analyzed in different welding *** results indicated two different connection modes:the chimeric mode and the non-chimeric *** corresponding depression depth are 2 and 2.4 mm,*** the non-chimeric connection mode,the steel/aluminum metallurgical interface is a smooth transition,the hook structure is obvious,and the welding mechanism mainly depends on the mutual diffusion between ***,in the chimeric mode,a hook structure will be formed at the metallurgical interface of steel and *** connection mechanism is determined by mechanical interlocking and mutual *** maximum strength value is 7.48 kN in non-chimeric *** this time,the spindle speed is 1300 r/min and the pressure speed is 1 mm/*** were two types of fractures:the button fracture mode and the peel fracture mode.

关键词： Friction stir spot welding 5052 aluminum alloy Q235 low-carbon steel Intermetallic compound Mechanical interlocking

Growth kinetics of cubic carbide free layers in graded cemented carbides

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International Journal of Minerals,Metallurgy and Materials 2012年第1期19卷 64-71页

作者： Liu-yong Shi Yi-min Liu ji-hua huang Shou-quan Zhang Xing-ke Zhao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China College of Mechanical and Electrical engineering Hainen University Danzhou 571737 China Xiarnen Golden Egret Special Alloy Co. Ltd. Xiamen 361006 China

In order to reveal the formation mechanism of cubic carbide free layers （CCFL）, graded cemented carbides with CCFL in the surface zone were fabricated by a one-step sintering procedure in vacuum, and the analysis on microstructure and element distribution were performed by scanning electron microscopy （SEM） and electron probe micro-analyzer （EPMA）, respectively. A new physical model and ki- netic equation were established based on experimental results. Being different f^om previous models, this model suggests that nitrogen diffu- sion outward is only considered as an induction factor, and the diffusion of titanium through liquid phase plays a dominative role. The driving force of diffusion is expressed as the differential value between nitrogen partial pressure and nitrogen equilibrium pressure essentially. Simulation results by the kinetic equation are in good agreement with experimental values, and the effect of process parameters on the growth kinetics of CCFL can also be explained reasonably by the current model.

关键词： graded materials cemented carbides diffusion kinetics

Modulation of Electrochemical Oscillations by Specific Adsorption of Cl- during the Electrooxidation of Methanol on Pt Electrode

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Chinese Chemical Letters 2002年第3期13卷 277-278页

作者： Ze Lin LI ji hua huang Xiao Ming XIAO Yue ZENG Xia CHU Department of Chemistry Hunan Normal UniversityChangsha 410081

Potential oscillation during the electrocatalytic oxidation of methanol can be modulated by the specific adsorption of Cl- on the platinum electrode, which suppresses the electrocatalytic oxidation of methanol, and makes the cross cycle in the cyclic voltammogram become smaller and finally disappear with the increase of Cl- concentration. The method is also applicable to the electrocatalytic oxidation of other small organic molecules.

关键词： Methanol chloride ions specific adsorption potential oscillation modulation.

Characterization of Cu_3P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 65-70页

作者： jian-xun Chen Xing-ke Zhao Xu-chen Zou ji-hua huang Hai-chun Hu Hai-lian Luo School of Materials Science and Engineering University of Science and Technology Beijing

This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of *** solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interracial micro- structure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like CuaP phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear test- ing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.

关键词： lead-free solders phosphorus melting temperature microstructure thermodynamics

Transcription and regulation of hepatitis B virus genes in host sperm cells

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Asian Journal of Andrology 2018年第3期20卷 284-289页

作者： Ying Zhong Dong-Ling Liu Mohamed Morsi M Ahmed Peng-Hao Li Xiao-Ling Zhou Qing-Dong Xie Xiao-Qing Xu Ting-Ting Han Zhi-Wei Hou ji-hua huang Lan Xu Tian-hua huang Department of Genetics Chengdu Jinxin Research Institute for Reproductive Medicine and Genetics Chengdu 610066 China Research Center for Reproductive Medicine Shantou University Medical College Shantou 515041 China Department of Gynecology and Obstetrics The First Affiliated Hospital Shantou University Medical College Shantou 515041 China

To investigate whether transcription of hepatitis B virus （HBV） gene occurs in human sperm, total RNA was extracted from sperm of patients with chronic HBV infection （test-I）, from donor sperm transfected with a plasmid containing the full-length HBV genome （test-2）, and from nontransfected donor sperm （control）, used as the template for reverse transcription-polymerase chain reaction （RT-PCR）. Positive bands for HBV DNA were observed in the test groups but not in the control. Next, to identify the role of host genes in regulating viral gene transcription in sperm, total RNA was extracted from 2-cell embryos derived from hamster oocytes fertilized in vitro by HBV-transfected （test） or nontransfected （control） human sperm and successively subjected to SMART-PCR, suppression subtractive hybridization, T/A cloning, bacterial amplification, microarray hybridization, sequencing and the Basic Local Alignment Search Tool （BLAST） search to isolate differentially expressed genes. Twenty-nine sequences showing significant identity to five human gene families were identified, with chorionic somatomammotropin hormone 2 （CSH2）, eukaryotic translation initiation factor 4 gamma 2 （EIF4G2）, pterin-4 alpha-carbinolamine dehydratase 2 （PCBD2）, pregnancy-specific beta-l-glycoprotein 4 （PSG4） and titin （TTN） selected to represent target genes. Using real-time quantitative RT-PCR （qRT-PCR）, when CSH2 and PCBD2 （or EIF4G2, PSG4 and TTN） were silenced by RNA interference, transcriptional levels of HBV s and x genes significantly decreased （or increased）（P 〈 0.05）. Silencing of a control gene in sperm did not significantly change transcription of HBV s and x genes （P 〉 0.05）. This study provides the first experimental evidence that transcription of HBV genes occurs in human sperm and is regulated by host genes.

关键词： embryo hepatitis B virus host gene regulation sperm transcription

Friction plug−riveting spot welding of AA 7075-T6 aluminum alloy and low carbon steel using 1045 steel rivet

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Transactions of Nonferrous Metals Society of China 2024年第12期34卷 3893-3904页

作者： Ya-jia LIU jian-yu LI Ze-hao XIE Shu-hai CHEN jian YANG ji-hua huang Zhi-yi ZHAO School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

7075-T6 aluminum alloy/low carbon steel joint was carried out via a novel friction plug−riveting spot welding *** process utilized uniquely designed steel rivets with a tip and groove *** macro-morphology formation,microstructure,microhardness and lap shear performance of joints were *** the spindle down distance increased,the rivet tip was friction welded with the lower steel sheet,resulting in the formation of a solid phase welding zone exhibiting metallurgical ***,a hook was formed in the joint,providing the mechanical *** results showed that under optimal parameters of spindle down distance of 3.4 mm,rotation speed of 4000 r/min,and spindle down speed of 2.4 mm/s,the lap shear load of the joints reached a maximum of 14.36 *** occurred at the aluminum alloy base metal.

关键词： friction plug-riveting spot welding aluminum alloy low carbon steel dissimilar metal joining

Effect of Si content on interfacial reaction and properties between solid steel and liquid aluminum

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Transactions of Nonferrous Metals Society of China 2021年第9期31卷 2570-2584页

作者： Tian-peng ZOU Gao-yang YU Shu-hai CHEN ji-hua huang jian YANG Zhi-yi ZHAO ji-ping RONG jin YANG School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Materials Engineering Shanghai University of Engineering ScienceShanghai 201620China

The effect of Si content on the microstructures and growth kinetics of intermetallic compounds(IMCs)formed during the initial interfacial reaction(<10 s)between solid steel and liquid aluminum was investigated by a thermophysical simulation *** influence of Si addition on interfacial mechanical properties was revealed by a high-frequency induction *** results showed that IMCs layers mainly consisted ofη-Fe_(2)Al_(5)andθ-Fe_(4)Al_(13).The addition of Si reduced the thickness of the IMCs *** growth of theηphase was governed by the diffusion process when adding 2 wt.%Si to the aluminum *** 5 wt.%or 8 wt.%Si was added to aluminum,the growth was governed by both the diffusion process and interfacial reaction,and ternary phaseτ1/τ9-(Al,Si)_(5)Fe_(3)was formed in theη*** apparent activation energies of theηphase decreased gradually with increasing Si *** joint with pure aluminum metal had the highest tensile strength and impact energy.

关键词： intermetallic compounds Si content solid steel liquid aluminum interfacial reaction mechanical properties

Effects of heat treatment on microstructure and microhardness of linear friction welded dissimilar Ti alloys

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Transactions of Nonferrous Metals Society of China 2013年第12期23卷 3540-3544页

作者：张传臣张田仓季亚娟黄继华北京航空制造工程研究所北京100024 北京科技大学材料科学与工程学院北京100083

A detailed investigation for the influence of post weld heat treatment （PWHT） on the microstructure of TC4 and TC17 dissimilar joints was analyzed. The fully transformed microstructure in the as-welded zone indicated that the peak temperature exceeded theβ-transus temperature at the weld interface during linear friction welding. TC4 side was mainly composed of martensiteα′phase with random distribution and it was singleβfor that of TC17. In the thermomechanically affected zones of TC4 and TC17, the structure undergoes severe plastic deformation and re-orientation, yet without altering the phase fractions. After PWHT, in the weld zone of TC4 alloy, the phase transformationα′→α＋βoccurred and the acicularαwas coarsened, which resulted in a decrease in hardness. In the weld zone of TC17 alloy, fineαphase precipitated at the grain boundary and withinβgrains, which resulted in a sharp increase in hardness.

关键词： linear friction welding Ti alloys heat treatments microstructure microhardness

Effects of germanium additions on microstructures and properties of Al-Si filler metals for brazing aluminum

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Transactions of Nonferrous Metals Society of China 2016年第3期26卷 775-782页

作者：牛志伟黄继华陈树海赵兴科北京科技大学材料科学与工程学院北京100083

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.

关键词： Al-Si-Ge filler microstructure brazed joint shear strength 1060 aluminum