LI Zhuo-ran, FAN Jian-xin, FENG Ji-cai. Interfacial Reaction of Brazing Joint of Alumina Ceramics to Mild Steel[J]. Journal of Materials Engineering, 2008, 0(9): 1-4.
Alumina ceramic was brazed in vacuum to mild steel with active brazing filler metal Ag-Cu-Ti3.The interfacial reaction products were determined by X-ray diffraction(XRD) method.The interfacial phases were analyzed using EDAX.It was shown that the interfacial reactions were complex and the interfacial reaction products were various,including Ti3Cu3O,Ti3Al,TiMn,TiFe2 and TiC etc.The gradual transition structures,alumina ceramic/Ti3Cu3O/Ti3Al+TiMn+TiFe2+Ag(s,s)+Cu(s,s)/TiC/mild steel were formed at the interface.
WANG Jian-xin, XUE Song-bai, HAN Zong-jie, YU Sheng-lin, CHEN Yan. Study on Wettability of Sn-Ag-Cu-Ce Solder and Mechanical Properties of Soldered Joints[J]. Journal of Materials Engineering, 2008, 0(9): 5-8.
The wettability of Sn-Ag-Cu-Ce solders on Cu substrate was determined by the wetting balance method,the mechanical properties of Sn-Ag-Cu-Ce joints were investigated,and the fracture morphologies of joints were also studied.It is found that the wetting times,and wetting angles of Sn-Ag-Cu-Ce solder are decreased with the increase of Ce content,and good wettability of Sn-Ag-Cu-Ce is obtained with around 0.03%-0.05%(mass fraction) Ce.The mechanical properties of soldered joints are enhanced with the addition of Ce,and the soldered joints possess the peak values of pull forces as well as improved ductility with obvious dimples when the Ce addition is about 0.03% in Sn-Ag-Cu-Ce joint.
NIE Zhong-ming, FU Li, REN Jie, XU Chong. Influence of Surface Treatment Technology on the Ultrasonic Welding Property Between the Down-lead and Au Electrode of CdZnTe Wafer[J]. Journal of Materials Engineering, 2008, 0(9): 9-12.
By means of scanning electron microscope and EDS test,the factors which have a great influence on the ultrasonic wire bonding between the CdZnTe(CZT) electrode and the Au down-lead are studied,such as surface treatment technology,electrode thickness of CZT wafer and ultrasonic welding parameters.The results show that CZT wafer with the mechanical polishing treatment was easier to achieve the ultrasonic wire bonding between the Au electrode of CZT and the down-lead.Moreover,the weldbility between the CZT electrode thickness and the down-lead shows a kind of parabola relationship.That's to say,there should be an optimal CZT electrode thickness(180nm in this research) for the high bonding rate when the electrode treatment technology had been fixed up.Besides,the welding power and the wedge pressure influence the ultrasonic wire bonding rate greatly.In this test,the optimal welding parameters were as follows: the power 2W,the pressure 60×10-3kg,welding time 20ms and the power for fire ball formation 1.5W.
ZHANG Li-xia, WU Lin-zhi, TIAN Xiao-yu, HE Peng, LIU Duo, FENG Ji-cai. Research on the Brazing of SiO2 Ceramic to TC4 Alloy[J]. Journal of Materials Engineering, 2008, 0(9): 13-16.
SiO2 glass ceramic was successfully joined to TC4 alloy using a commercially available AgCu filler foil by vacuum brazing.Joint interface was identified by several analysis methods,such as SEM,EDS and XRD.The typical interface structure is TC4/Ti2Cu+Ti(s.s)/Ti2Cu/TiCu+Ti3Cu4+Ag(s.s)/Ag(s.s)+Cu(s.s)+TiCu/TiCu+Cu2Ti4O/Al2(SiO4)O+TiSi2/SiO2 from TC4 alloy to SiO2 glass ceramic side.The effect of brazing parameters on joint interface was studied.According to the experimental results,the joint brazed at 850℃ for 5min has the maximum shear strength of 30MPa.
ZHAO Hai-sheng, PAN Hui, SUN Ji-sheng, LI Da-bin. Microstructure and Technology Parameter Control of the K640 Brazed Joint[J]. Journal of Materials Engineering, 2008, 0(9): 17-19,24.
The cast cobalt-based superalloy,named K640,was brazed under different technology parameters.The microstructure and phase composition of the joints were observed and analyzed by means of SEM,EDX and XRD.The results showed that joints,with similar compositions,were made up with cobalt-based solution,M23C6,eutectics of M3B2+cobalt-based solution and small block of MC.As the brazing temperature was low or the holding time was short,lots of low-melting M3B2 were precipitated in the central part of the brazing seam.On the other hand,with the increasement of brazing temperature and holding time,the amounts of M3B2 and MC were decreased while more coarsened M23C6 precipitated in the brazing seam.
LIU Jie, QIU Xiao-ming, ZHU Song, SUN Da-qian. Microstructure and Properties of Bonding Interface of Ni-Cr/Ti/Multiple Porcelain[J]. Journal of Materials Engineering, 2008, 0(9): 20-24.
Ti film was sputtered on Ni-Cr alloy substrate with magnetron sputtering and so it acted as an interlayer for Ni-Cr/porcelain interface.Microstructure and properties of bonding interface of Ni-Cr/Ti/multiple porcelain have been investigated.Experimental results showed that the Ni-Cr/Ti/porcelain interface was compact,and there was no crack or flaw at the interfaces.The reaction at the Ni-Cr/Ti/porcelain interface was very complicated and the interface has new phase composition with SnCr0.14Ox,NiCr2O4,Cr2O3,TiO2,AlTi3 and Ti2Ni.The types,quantity and distribution of the interface reaction products were affected by the thickness of Ti interlayer,firing temperature and firing time,which finally determined the bond strength of Ni-Cr/Ti/porcelain interface.The bond strength reached 40.2MPa at firing temperatures of 990℃ for firing time of 2.5min,and the bond strength of Ni-Cr/Ti/porcelain interface reached 48.4MPa with Ti thickness of 3μm.
YU Zhi-shui, LI Rui-feng. Interfacial Structure and Properties of Galvanized Steel Sheet Joined by Pulsed Arc Brazing Process[J]. Journal of Materials Engineering, 2008, 0(9): 25-27,31.
The galvanized steel sheet is joined by pulsed arc brazing process,the joint interfacial structures and properties of the joints at different pulse frequencies are studied.It can be seen that the agitation and brushing action of the molten pool is increasing with the increasing of pulse frequencies ranging from 100 Hz to 2000 Hz,then the whisker-like intermetallic compound fragmentation behavior is strengthened and the constitutional super cooling zone is broadened from 40μm to 120 μm.At last,the dispersal quantity and width of fine Fe5Si3(Cu) particles are increased in brazing joint which lead to the improvement of the joint mechanical properties,and the maximum micro-hardness of the interfacial zone is elevated from 175 MPa to 204 MPa.
ZHANG Lei, TENG Jun-fei, HOU Jin-bao. Diffusion Bonding of 0.4% Mass Fraction Hydrogenated Ti600 Alloy[J]. Journal of Materials Engineering, 2008, 0(9): 28-31.
The diffusion bonding of hydrogenated Ti600 alloy containing mass fraction 0.4% hydrogen and the mechanical property test were carried out.The diffusion holes close-up ration and fracture were investigated by means of optical metallographic microscope,scanning electron microscope.The results show that the hydrogen is beneficial to increasing the holes close-up ratio of Ti600 diffusion welding.With the diffusion bonding parameters increasing the diffusion holes decrease gradually.When bonded at 875℃ for 60min under a pressure of 5MPa,the diffusion holes disappeared and the tensile strength of the joint was up to 1013MPa,which reached 96% that of the base metal,and the fracture exhibited dimple pattern.
LI Xiao-yi, LUO Zhen, BU Xian-zheng, AO San-san, YUAN Shu-xian, SONG Kai-lei, XUE Zhi-qing. Study on Active Brazing of Al2O3 Ceramic and Ni[J]. Journal of Materials Engineering, 2008, 0(9): 32-35,39.
It is difficult to join ceramic and metal because of differences in physical and chemical properties.In this experiment,Al2O3 ceramic and Ni had been brazed with Ag-Cu-Ti active alloy.The result of shear test indicated that strength of brazing joint was the highest one when brazed at 1000℃.When the temperature was less than 960℃,active alloy could not join Al2O3 ceramic and Ni.But the strength of brazing joint decreased at higher than 1000℃.The microstructure of joint had been analyzed by material test analysis methods.The results showed that Cu distributed averagely in joint.The gathering phenomena of Ag appeared.Ti distributed on both sides of joint.The element of products included Cu,Ti,Al,Zr,O and so on.Complex compounds which generated from the reaction among Cu,Ti and Al2O3 ceramic jointed ceramic and metal.
WANG Zhi-ping, HUANG Ji-hua, BAN Yong-hua, XIONG Jin-hui, ZHANG Hua, ZHAO Xing-ke. Microstructure of Reactive Composite Brazing Joints of Cf/SiC Composites and Ti Alloy with Cu-Ti-C Filler Material[J]. Journal of Materials Engineering, 2008, 0(9): 36-39.
Using the mixed powder of Cu,Ti and graphite Cf/SiC composite was brazed to Ti alloy under vacuum condition.The joints were investigated by X-ray diffraction,scanning electron microscopy and energy dispersive spectrometry.The results show that fine brazed joints of Cf/SiC composite/Ti alloy are acquired at 950℃ for 20min using Cu-25Ti(mass fraction/%) with the addition of proper graphite as brazing alloy.In-situ synthesized TiC which reduces the thermal stress significantly is obtained during vacuum brazing.TiC reaction layer around surplus graphite and TiC particles in the bonding layer are synthesized by interdiffusing of C element and Ti element in the liquid bonding layer.The reaction rate is controlled by the diffusion rate of C element from graphite particles to liquid bonding layer.
DUAN Zhen-zhen, SUN Da-qian, ZHU Song, QIU Xiao-ming. Microstructure and Property of Ti/Zr/Porcelain Interface[J]. Journal of Materials Engineering, 2008, 0(9): 40-43,47.
A ZrN film was sputtered on polished titanium substrate using magnetron sputtering technique.The microstructure and property of Ti/Zr/porcelain interface were investigated.The results show that the interface between porcelain and titanium is composed of oxide layer formed on titanium and reaction zone which mainly contains Ti,Si and O.The joint of Ti/porcelain translates into Ti/Zr/porcelain after the deposition of ZrN coating.The ZrN film can effectively prevent the formation of oxidation layer on titanium.The bonding strength of Ti/Zr/Porcelain is 29.2MPa,comparing with 23.5MPa of Ti/porcelain increased by 24.3%.
YAN Keng, MA Zhi-xin, ZHANG Jian. Effect of Alclad on Mechanical Property of FSW Joint[J]. Journal of Materials Engineering, 2008, 0(9): 44-47.
High purity aluminum or allumen(including 1% Zn,mass fraction) alclad on 2024 aerolite is usually employed for improving corrosion resistance.This alclad will greatly impact the mechanical properties of friction stir welded joint.Mechanical properties and microstructures of varied welded alclad aluminum 2024-T3 were investigated.It was found that the mechanical properties of the joints decreased by the alclad and it will be increased dramatically by removing the alclad.The effect of alclad on the bottom surface is larger than on the top surface.The mechanical properties of 2024-T3 joints will fall down because alclad is entrapped into the welded joints by the rotating and stirring tools during the friction stir welding,similar with "inclusion" in fusion welding.
WANG Ying-ling, LI Hong, LI Zhuo-xin, FENG Ji-cai. Research on Transient Liquid Phase Diffusion Bonding Process of TiNi Shape Memory Alloy to Stainless Steel[J]. Journal of Materials Engineering, 2008, 0(9): 48-51,55.
Transient liquid phase diffusion bonding(TLP-DB) of TiNi shape memory alloy(SMA) to stainless steel was performed with AgCu foil as interlayer.The effect of bonding temperature,holding time and bonding pressure was also investigated.The results showed that the maximum shear strength of the joint was obtained for the specimens joined at 860℃ for 60 minutes with a specific pressure of 0.05MPa.Through scanning electron microscopy(SEM) and X-ray diffractometry(XRD) test,the element distribution and phase composition of the joint welded under the optimum process parameters were investigated.It indicated that the joint property was significantly influenced by the formation of intermetallics TiNi2,TiFe and Ti3Ni4 etc.
HUAI Jun-feng, GUO Wan-lin, LI Tian-wen, YUAN Hong, JIANG Wei. Weldabilities of the Oxide-dispersion-strengthened Superalloy MGH956[J]. Journal of Materials Engineering, 2008, 0(9): 52-55.
Oxide-dispersion-strengthened(ODS) MGH956 superalloy is one kind of superalloy fabricated by mechanical alloying process.The weldabilities of MGH956 are investigated using TIG welding and electron beam welding,as well as vacuum brazing technology accompanied with diffusion process.The microstructure of joint is studied by means of SEM.At room temperature,the joint tensile strength reached about 95%of the base material for the above three joining methods.It is found that there are more pores in the TIG welding joint than the electron beam welding joint.In the view of high temperature strength of the joints,vacuum brazing method is superior to other two methods.
WANG Zhi-hui, YANG Ai-di, ZHANG Tian, HE Ding-yong. Dissolution Behavior of WC in WC Reinforced Composite Coatings[J]. Journal of Materials Engineering, 2008, 0(9): 56-59,63.
The dissolution behavior of WC in three different nickel matrix systems is investigated.The results show that the dissolution occurs at the rim of WC with the precipitation of Fe6W6C in Ni60A-WC coatings;WC are loosely-separated,bridge-bonded and reunited to coarse carbide groups in Ni25B-WC coatings;in Ni22AA-WC coatings the WC are slightly dissolved in some locations.The larger concentration gradient of W and C between WC particles and matrix,and higher Cr and Fe contents will accelerate the dissolution of WC particles.
JIN Yu-hua, WANG Xi-jing, LI Chang-feng, MA Ning-ning. Effect of Base Metal on Joint Properties of Friction Stir Welded[J]. Journal of Materials Engineering, 2008, 0(9): 60-63.
Three different aluminium alloy plates of 5mm thickness 2024,6082 and 7050 were welded by FSW.The results show that some defects such as holes appear easily in the joint zone for aluminium alloy 2024,but the tensile strength of joint can not decrease predominantly when the size of hole is lower than certain value.For aluminium alloy 6082,the formation of joint is super to that of aluminium alloy 2024 and 7050,its tensile strength raises or decreases 5MPa with various welding parameter.Hole defeat hasn't been found in the joint under the welding parameters which were designed in this experiment,however,the ratio of tensile strength of joint to base material is lower comparing with aluminium alloy 2024 and 6082.Because the properties of FSW joint were also influenced by the material properties such as the yield strength,ductility and hardness of base metal besides FSW process parameter.
CHEN Bo, XIONG Hua-ping, MAO Wei, CHENG Yao-yong. Microstructure of the SiCf-reinforced Titanium Based Composite Joint and Joining Mechanism[J]. Journal of Materials Engineering, 2008, 0(9): 64-66,70.
The vacuum brazing test of SiCf/β21S titanium matrix compound was carried out and the joint microstructure was investigated.The results indicated that the elements Cu,Ni and Co diffused thoroughly into the whole joint,which decreased the quantity of Ti-M(M=Cu,Ni,Co) compounds per unit volume.In addition,because both Al and Mo are elements of β-phase formation and they existed in the joint with great quantity,the similar β-phase microstructure was observed in the joint and the base metal.The mechanical properties of the SiCf/β21S joints will be increased due to the above two reasons.
MA Li, HE Ding-yong, WANG Li-zhi, JIANG Jian-min, LI Xiao-yan. Phase of Brazing Seam and Mechanical Properties of Magnesium Alloy AZ31B Brazed Joint[J]. Journal of Materials Engineering, 2008, 0(9): 67-70.
Induction brazing of wrought magnesium alloy AZ31B using Al matrix filler metal was investigated.Both the phases of brazing seam and the mechanical properties of brazed joint were studied.The interface structure and formation phase of brazing seam of the brazed joint were investigated by scanning electron microscopy,X-ray diffraction and X-ray electron probe microanalysis.The tensile strength of joint and the microhardness of the formation phases were also tested.The results show that Al matrix filler metal has reacted with the base metal and α-Mg,β-Mg17(Al,Zn)12 phases have been produced in brazing seam.Average tensile strength of the butted joint reached 42MPa and average shear strength of the overlapped joint reached 27MPa.The joint mainly exhibits intergranular fracture mode and the fracture comes from β-Mg17(Al,Zn)12 hard brittle phase.
TIAN Liang, HUANG Ji-hua, ZHANG Zhi-yuan, ZHAO Xing-ke, ZHANG Hua. Research About Brazing Si/SiC Ceramics and Invar Alloy Using Ti50Cu+W Solder[J]. Journal of Materials Engineering, 2008, 0(9): 71-75.
The Si/SiC ceramics and invar alloy was brazed by using Ti50Cu+W solder and vacuum brazing.The microstructure of the joint was observed and analyzed,the mechanical property of the joint was measured.Effect of parameter and content of wild phase W on microstructure and mechanical property was studied.So compacted brazing joint between the Si/SiC ceramics and invar alloy can be achieved by using Ti50Cu+W filler.When the volume fraction of W is 30%,the brazing temperature fixed at 970℃,and the holding time 5 min,the highest shear strength of 106MPa can be obtained.
HAN Zong-jie, XUE Song-bai, WANG Jian-xin, ZHANG Liang, YU Sheng-lin. Study on Wettability and Spreadability of Lead-free Solder with Diode Laser Soldering Process[J]. Journal of Materials Engineering, 2008, 0(9): 76-79.
Wettability and spreadability of Sn-Ag-Cu lead-free solder on Cu substrate were tested by diode laser soldering system,influence of different soldering parameters on wettability and spreadability of Sn-Ag-Cu lead-free solder was studied.The results indicate that,as the laser output power increases,the spreading area of lead-free solder increases and the wetting angle decreases,the optimal wettability and spreadability is obtained while the laser output power increase to a certain range.Within a certain laser output power,the wettability and spreadability of Sn-Ag-Cu lead-free solder becomes better as the increase of laser soldering time,and it reaches the optimal state when the laser soldering time increase to a certain range.While the laser output power is too low or too high,the wettability and spreadability of Sn-Ag-Cu lead-free solder on Cu substrate is always poor whatever the laser soldering time is short or long.
XIE Feng-chun, HE Peng, CAO Jian, FENG Ji-cai. Microstructure and Properties of Brazed Graphite and Copper Joints[J]. Journal of Materials Engineering, 2008, 0(9): 80-84.
Graphite was joined to copper using amorphous TiZrNiCu filler foil by vacuum brazing.Joint interface was analyzed by several methods,such as optical microscope,SEM,EDS and EPMA.The results showed that Cu-Ti,Cu-Zr and Ni-Ti compounds distributed on the interface and cracks tended to occur at large-size compounds.Cu-based solid solution can prevent or slow down the crack propagation,which is favorable for the joint strength.When the joint is brazed at 950℃ for 5min,the resistance of joint is below 5 mΩ and the average resistance is 3.3mΩ,while the joint shear strength reaches 16.34MPa.All of these meet the demand of the joint as a diverter.
