Zn Filler Metal Research Articles

Brazed Joint Interface Bonding Strength of AR500 Steel and AA7075 Aluminium Alloy

The joining of aluminium alloys to steels has been extensively studied, especially in the automotive sector. However, aluminium alloys are known to be difficult to join with steels when methods involving fusion welding are used because of the hot cracking problem. Hence, a high-strength joint between these dissimilar metals would be of benefit especially in reducing the weight of products. In this work, the torch-brazing method was applied to join AR500 steel with AA7075 aluminium alloy using Al–Si–Zn base filler metal at various flame times. The effects of the brazing work on the intermetallic phase formation and the mechanical strength of the joints were investigated. In this work, the maximum shear load obtained was 6460 N and the presence of the intermetallic phases had reduced the shear strength of the brazed joints. However, the torch-brazing process using Al–Si–Zn filler metal had successfully facilitated the joining of these dissimilar metals.

Microstructure evolution and mechanical properties of 5083 aluminum alloy joints by ultrasonic soldering

Aluminum alloy 5083 was joined with Sn–[Formula: see text]Zn ([Formula: see text], 5, 9, 30 and 60 wt.%) filler metal by ultrasonic soldering at 400[Formula: see text]C. The joint microstructure consisted of [Formula: see text]-Sn and [Formula: see text]-Al solid–solution phases when using pure Sn solder. Zn-rich phases were observed in the joints with Sn–Zn filler metal. The Zn-rich phases grew thicker and larger with the increase in Zn content in the filler metal. The joints soldered with Sn–30Zn filler metal reached a maximum shear strength of 70 MPa. Joint cracking occurred at the interface of pure Sn and Sn–9Zn solders as indicated by SEM observation of the fracture surfaces. The locations of the fracture surface moved from the interface to the seam when using the Sn–30Zn or Sn–60Zn filler metal. The coarse Zn-rich phases were also observed on the fracture surface using Sn–60Sn solder, which results in a shear strength reduction of the joints.

Effect of intermetallic compounds on mechanical properties of copper joints ultrasonic-soldered with Sn-Zn alloy

The transformation of the intermetallic compounds (IMC) at the interface of Sn-Zn solder and Cu substrate by an ultrasonic-assisted soldering method with the variation of Zn content was investigated. The formation of IMC at the solder/Cu interface is controlled by the Zn content in the filler metals. The IMC layer of Cu6Sn5 forms if the mass fraction of Zn is lower than 0.5wt.%. The IMC becomes a single-layered Cu5Zn8 if the mass fraction of Zn exceeds 1wt.%. The layer of Cu5Zn8 thickens with the increase of Zn content. Joints with an IMC layer of Cu5Zn8 exhibit a higher strength than that with Cu6Sn5. In the joints soldered with the Sn-0.5Zn filler metal, fractures occur inside the Cu6Sn5 IMC grains. In the joints with the Zn content higher than 1wt.%, fractures propagate along the Cu5Zn8 IMC/solder interface. The locations of the fracturing are associated with the micro-cracks that existed at the IMC grains.

Effect of Ti Addition to Zn Filler Metal on Wettability and Reinforcement of Soldered Joint of Aluminum

This article presents the phisicochemical propreties of aluminium brings a lot of difficulties during soldering one of tchem is low melting point. The work also presents results of mechanical and metallographic investigations. Structural examination was performed by means of light microscopy and mechanical properties with the aim of shear strength test. On the basis structural investigation joints made with Zn and Zn with Ti addition indicated possibilities of reinforcement of soldered joint of aluminium

Microstructure and shear strength of sintered Cu–Al2O3 composite joined to Cu using Ag–Cu and Cu–Zn filler alloys

The microstructure and shear strength of joints between Cu–Al2O3 (50vol.% Al2O3) composite and Cu metal brazed with 72Ag–28Cu and 70Cu–30Zn filler metals were characterized. The composite fabricated by the pulsed electric current sintering of Cu-coated alumina particles showed less than 2% residual porosity and interesting thermophysical properties for electronic packaging applications; thus, the adhesion of the composite to copper metal was evaluated. The composite–Cu assemblies were brazed in an inert atmosphere at working temperatures of 10, 60 and 110°C above the liquidus of the alloys. In the case of Ag–Cu, there was significant diffusion of silver to the composite side, forming a (Ag, Cu) solution. Zinc diffused to the copper side when using the Cu–Zn filler metal, and the formation of fine oxygen-containing Zn precipitates was observed; furthermore, the overheating of the Cu–Zn material originated in interfacial cavities due to evaporation and the zinc deficiency of the fused metal, which reduces its fluidity. The shear strength followed a similar trend with respect to temperature for both joining systems; maximum strengths of 49.9 and 37.1MPa were obtained for the 72Ag–28Cu and 70Cu–30Zn fillers, respectively, at the intermediate temperatures used. Fracture examination revealed that the brazed arrays failed in all cases on the composite side. The microstructure and strength values indicate a strong adhesion between the parts, which constitutes an important requirement for thermal management in electronic assemblies.

Effect of calcium on the microstructure and mechanical properties of brazed joint using Ag–Cu–Zn brazing filler metal

The induction brazing of 316LN stainless steel using Ag–Cu–Zn filler metal containing various content of Ca was carried out to investigate the influence of impurity element Ca on the microstructure and mechanical properties of the brazed joint. The results showed that Ca additions caused the coarser of the grains and their irregular distribution. Increase of the Ca content resulted in the formations of brittle intermetallic compounds (IMCs) CaCu which perhaps lead to the formations of voids. All of the calcium-containing brazed joints performed better in microhardness than calcium-free ones and brazed joints containing 0.003wt.% Ca showed the highest microhardness of 203HV. While the tensile strength decreased with the increment of Ca, from 460MPa to 400MPa. The combination effects of coarser grains, brittle IMCs and voids conduced to the reduction of tensile strength and microhardness of the brazed joints.

Effect of Al foils interlayer on microstructures and mechanical properties of Mg–Al butt joints welded by gas tungsten arc welding filling with Zn filler metal

Gas tungsten arc butt welding of Mg–Al filling with Zn filler metal without and with Al foils in different thicknesses was carried out. Additional Al element was introduced into the fusion zone to accurately modulate microstructure and composition of the welding seam. Microstructures and mechanical properties of the welded joints were examined. Results show that the addition of appropriate quantity of Al element increases the content of Al-based solid solution in the fusion zone near the Mg base metal. The solid solution can eliminate the stress concentration and hinder crack propagation, so the tensile strengths of the joints are improved. However, the immoderate quantity of Al element will lead to the formation of partially Al-rich zones and deteriorate the mechanical property of the joints.

Microstructure evolution of Al/Mg butt joints welded by gas tungsten arc with Zn filler metal

Abstract Based on the idea of alloying welding seam, Gas tungsten arc welding method with pure Zn filler metal was chosen to join Mg alloy and Al alloy. The microstructures, phases, element distribution and fracture morphology of welding seams were examined. The results indicate that there was a transitional zone in the width of 80–100 μm between the Mg alloy substrate and fusion zone. The fusion zone was mainly composed of MgZn 2 , Zn-based solid solution and Al-based solid solution. The welding seam presented distinct morphology in different location owning to the quite high cooling rate of the molten pool. The addition of Zn metal could prevent the formation of Mg–Al intermetallics and form the alloyed welding seam during welding. Therefore, the tensile strengths of joints have been significantly improved compared with those of gas tungsten arc welded joints without Zn metal added.

Fluxless joining of aluminium alloy to steel by laser irradiation method

A6061 aluminium alloy was joined with steel using Zn filler metal under laser irradiation process. The quality of joint was evaluated by the strength of a lap joint. The effects of laser power irradiation conditions such as travelling speed and defocused distance on the joint strength were investigated. The maximum joint strength was obtained at relatively medium laser travelling speed. The excess reaction between filler metal and aluminium formed thick brittle intermetallic compounds between steel and aluminium alloy. The compounds are considered to lead to the reduction in joint strength. It was found that low wetting at high travelling speed and excess reaction layer formation at low travelling speed were responsible for low joint strength. The study revealed that the relatively high joint strength between aluminium alloy and steel was obtained by laser joining method using Zn filler without the use of flux in air atmosphere.

The relationship between microstructure and properties of Mg/Al brazed joints using Zn filler metal

This work focuses on the microstructure and properties of Mg alloy and Al alloy brazed joints prepared with different thickness of Zn filler metal, ranging from 0 to 30 μm. Mg alloy and Al alloy can be bonded successfully by Contact Reaction Brazing (CRB) with and without Zn filler metal in a traditional air furnace. The addition of the Zn filler metal can significantly improve the tensile strength. The reaction layer became thin with the use of thinner Zn filler-metal layers, while the thinner reaction layer brought about higher shear strength. The best results were associated with a bonding temperature of 360 °C and the use of a 3 μm Zn filler metal to produce bonded joints in times ranging from 10 to 30 min.

Microstructure and strength of TiC cermet/cast iron brazed with Ag – Cu – Zn filler metal

The brazing of TiC cermet to cast iron was carried out at 1223 K for 5 – 30 min using Ag – Cu – Zn filler metal. The formation phases, interface structures and shear strengths of the joints were investigated. The experiment result and analysis identify that three new phases, namely Cu base solid solution, Ag base solid solution and (Fe, Ni) have formed during the brazing of TiC cermet to iron. The interface structure of the joints can be expressed as TiC cermet/Cu base solid solution/Ag base solid solution + a little Cu base solid solution/Cu base solid solution + (Fe, Ni)/cast iron. The highest shear strength of the joints is 292.0 MPa, obtained with a brazing time of 20 min.

Interface structure and strength of brazed joints between TiC ceramic and iron

The brazing of TiC ceramic to iron was carried out at 1123–1273 K for 5–20 min using Ag–Cu–Zn filler metal. Interface structure and shear strength of joints were investigated, the former via electron probe microanalysis, scanning electron microscopy, and X-ray diffraction, and the latter via the shearing method. The results show the formation of three phases in the TiC ceramic–iron joint, namely, copper base solid solution, FeNi, and silver base solid solution. The highest joint shear strength of 256.5 MPa is obtained for a brazing temperature of 1173 K and brazing time of 5 min.

銀基ろうによるチタンの大気中ろう付

In this study, we developed Ag-based filler metals and new fluxes in order to braze commercially pure titanium in the air.The fluxes consisting of AgCI or CuCl added with small content of LiF can provide good wetting of the Ag-based filler metals on the titanium surface. In particular, the flux with the composition of 90%AgCI-10%LiF is the most effective from the viewpoint of the wetting and the joint strength. The joint brazed with 70%Ag-30%Zn filler metal through the metallizing process shows higher tensile strength than that of the joint brazed with the conventional filler metal.The adequate addition of copper to 70Ag-30Zn filler metal increases the strength of the brazed joint, but the addition of nickel to the Ag-Zn-Cu system filler metal is harmful to the strength of the joint.