Diffusion welding SiC_p/ZL101 with Ni interlayer

Through the vacuum diffusion welding SiC_p/ZL101 aluminum with Ni interlayer,the effect of welding parameter and the thickness property of Ni on the welded joint wasinvestigated, and the optimal welding parameters were put forward at the same time. Themicrostructure of joint was analyzed by means of optical-microscope, scanning electron microscope(SEM) in order to study the relationship between the macro-properties of joint and themicrostructure. The results show that diffusion welding with Ni interlayer can be used for weldingaluminum matrix composites SiC_p/ZL101 successfully. Under the welding parameters T=560℃, P=5 MPa,t=60 min, H=14μm, the bonding strength of welded joint can up to 121 MPa. Moreover, the thicknessof interlayer should match with the size of reinforced particles. If the thickness of interlayer istoo thin, it would have no effect on the welded joint beneficially. If the thickness of interlayeris too thick, it would cause the 'no-reinforcement zone' to appear.

Impulse pressuring diffusion bonding of titanium to 304 stainless steel using pure Ni interlayer

In the present study, impulse pressuring diffu- sion bonding technology （IPDB） was utilized between commercially pure titanium and 304 stainless steel （SS） using pure nickel （Ni） as interlayer metal. The interfacial microstructures of the bonded joints were investigated by scanning electron microscopy （SEM） and energy dispersive spectroscope （EDS） analyses. It is found that with the aid of the Ni interlayer, the interdiffusion and reaction between Ti and SS can be effectively restricted and robust joints can be obtained. Intermetallic compounds （IMCs） including Ti2Ni, TiNi, and TiNi3 are detected at the Ti/Ni interface; however, only Ni-Fe solid solution is found at the Ni/SS interface. The maximum tensile strength of 358 MPa is obtained by IPDB for 90 s and the fracture takes place along the Ti2Ni and TiNi phase upon tensile loading. The existence of cleavage pattern on the fracture surface indi- cates the brittle nature of the joints.

Diffusion Bonding of Ti-6Al-4V to QAl 10-3-1.5 with Ni/Cu Interlayers

Ti-6Al-4V and QAl 10-3-1.5 diffusion bonding has been carried out with Ni/Cu interlayers. The diffusionbonded joints are evaluated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and microhardness test. Intermetallic compounds at the interface zone are detected by X-ray diffraction （XRD）. Interracial microstructure of TiNi＋CuTi3＋α-Ti forms at the Ni/Ti-6Al-4V transition zone and Cu （ss. Ni） solid solution forms between Ni/Cu interlayers. The thickness of reaction layer （TiNi） increases with bonding time by a parabolic law： y^2=Koexp（-150000/RT）t, and K0=2.g×10^-7 m^2/s is figured out from the experiment data.

Effect of Interlayers on Microstructure and Properties of 2205/Q235B Duplex Stainless Steel Clad Plate

In this research,2205/Q235 B clad plates were prepared by a vacuum hot rolling composite process.The effects of adding Fe,Ni,and Nb interlayers on the bonding interface structures and the shear strengths of the clad steel plates were studied.The results showed that 2205 duplex stainless steel and the three interlayers produced a large amount of plastic deformation and low-angle boundaries,and the main structures were the recrystallized and deformed grains.There were many recrystallized grains in the microstructure of the Q235 B low-carbon steel due to the low deformation in the rolling process.The Fe interlayer had better wettability with the two kinds of steel,but the lower strength led to the reduction of shear strength by about14 MPa compared with the original clad steel plate.The C element in the Q235 B low-carbon steel easily diffused into the Fe interlayer,and the clad steel plate attained a poor corrosion resistance because a large decarburization area was formed.The Nb interlayer reacted with the Mo element in the 2205 duplex stainless steel to form an Nb-Mo binary alloy,which generated long-banded ferrite.The decarburization area was also produced because the Nb reacted with the C element in the Q235 B to form hard and brittle NbCx.As a result,the shear strength was significantly reduced by about 282 MPa,and the corrosion resistance of the bonding surface was deteriorated.The Ni interlayer did not react with the alloy elements in both sides,and therefore effectively prevented element diffusion and improved the corrosion resistance of the bonding surface.Due to the low strength of the Ni interlayer and the increased number of bonding surfaces of the clad steel plates,the shear strength was reduced to some extent(about 40 MPa),but it still met the engineering application standards.