Papers by Keyword: Bonding Strength

Abstract: This study investigates the bonding properties of transient liquid phase diffusion bonding using Cu/Sn electroplated films. A Cu substrate was electroplated with Cu and Sn films, followed by TLP bonding with a Ni substrate at 280°C under air atmospheric conditions without bonding pressure. Bonding times of 1, 3, and 30 min were employed to evaluate the effect of bonding duration on interfacial microstructure and shear strength. Cross-sectional microstructural analysis using EPMA revealed the formation of a Cu–Ni–Sn reaction layer at the bonded interface, with the thickness of this layer increasing as bonding time increased. Voids were observed at all bonding times, particularly at 30 min, where extensive void formation led to incomplete bonding. Shear test showed that shorter bonding times yielded higher average strengths, while longer bonding times resulted in a reduction due to void-induced degradation. Fracture surface observations confirmed that failure occurred within both the Sn and reaction layer, regardless of bonding time.

Abstract: Preparation of titanium alloy coating on the low carbon steel surface is an effective way to ensure the service performance of steel in marine environment. In this work, the effect of Cu interlayer thickness on the microstructure and properties of the titanium alloy coating was systematically studied. The results showed that a thin Cu interlayer cannot inhibit the diffusion of iron, and the Fe-Ti intermetallic compound (IMC) layer at the coating/substrate interface weakens the bonding property of the coating. And iron compounds on the surface of the coating surface are negative for corrosion resistance. The thickening of Cu interlayer inhibits the diffusion of iron and increases the shear strength of the coating by 40%～60%. When the iron compound is not present on the coating surface, the optimal electrochemical properties of the titanium alloy coating were achieved. However, the excessive thickness of the Cu interlayer will accelerate the heat loss of the molten pool and lead to the fusion defect in the initial cladding stage. In this study, the optimum thickness range of Cu interlayer (290μm ~ 375μm) was obtained. When the interlayer was in this range, titanium alloy coatings with excellent comprehensive properties could be prepared.

Abstract: The inner-lined layers bonding strength of the ceramic-lined tubing was measured from 25°C to 600°C. The macroscopic structure and microscopic characteristics of the slippage surface of the ceramic-lined tubing were observed using optical microscopy and scanning electron microscopy. Combined with finite element analysis of the residual stress distribution at different temperatures, the shear failure model of the ceramic-lined tubing at different temperatures was given. The mechanical bonding force at the C-A (ceramic layer-alloy layer) interface is greater than the metallurgical bonding force at the A-T (alloy layer-base tubing) interface at low temperature, and the mechanical bonding force at the C-A interface is less than the metallurgical bonding force at the A-T interface at high temperature. The transition temperature is about 200 °C.

Abstract: Laminated metal composites are composed of alternating layers of metals or alloys, bonding together at their interface, which have gained extensive attention because of their advantages such as improved fracture toughness, impact behavior, corrosion, wear and damping capacity. Roll bonding is the most widely used method to process many metallic composites. In this study, we fabricated some kinds of Al/Ti/Al sandwich-like laminated composites by cryogenic roll bonding. We find that cryogenic roll bonding techniques can improve the mechanical properties of laminated composites. Finally, we will discuss the mechanism of improvement in bonding strength and mechanical properties.

Abstract: Finite element analysis (FEA) has been proven to be a precise and applicable method for evaluating dental implant systems. This is because FEA allows for measurement of the stress distribution inside of the bone and various dental implant designs via simulation analysis during mastication where such measurements are impossible to perform in-vitro or in-vivo experiment. That is why the relationship between implant design and load distribution at the implant bone interface is a crucial issue to understand. This research study focuses on a static simulation and bonding strength for PLA/HA coating on V thread design of dental implant using three-dimensional finite element. The average masticatory muscle that involves in human biting such as X, Y and Z direction will be used to simulate force with load condition of 17.1N, 114.6N and 23.4N respectively. Based on result obtained, the coated dental implant model is more compatible than uncoated model due to lower maximum stress which is reduce about 16%. The coated model also shows lower deformation and higher bonding strength. Outcomes from this research provide a better understanding of stress distribution characteristics that would be useful in order to improve design of dental implant thread and evaluation of the PLA/HA bonding strength applied.

Abstract: The effects of rolling deformation on the interface bonding strength and microstructure of bimetallic clad plates were simulated. The composition and sub-structure of the interface were analyzed by electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). The results showed that the interfacial bonding strength of clad plates was significantly depend on the deformation process, and the bonding time was also a significant factor on bonding effect apart from total strain in the two-stage rolling. Chromium, nickel and other alloying elements have a significant diffusion zone at the bonding interface with a diffusion width of about 10µm. High resolution TEM analysis confirmed that there was an sound metallurgical bonding at the interface, and the structure of martensite in transition zone and matrix approximately meet the coherent relationship of(200) Ferrite // (111) Martensite and [020] Ferrite // [211]Martensite.

Abstract: This study investigates a brazing method for manufacturing PbTe thermoelectric modules using a Ag-based filler metal with a melting point of about 650 °C. To improve the bonding strength between the Ag-based brazing layer and the PbTe thermoelectric module, an electroless Ni-P plating layer is formed on the surface of the thermoelectric module as a diffusion barrier layer. The bonding strength of the PbTe thermoelectric module manufactured by the electroless Ni-P plating and Ag-based brazing has a high value of approximately 8.3 MPa. No defects such as pores or cracks were observed at the bonding interface between the thermoelectric element and the brazing layer. Furthermore, because of the high bonding strength of the manufactured thermoelectric module, fractures occur inside the thermoelectric element rather than at the bonding interface. Accordingly, the electroless Ni-P plating and Ag-based brazing method proposed in this study is found to be effective in manufacturing PbTe-based thermoelectric modules with high bonding strength.

Abstract: The bonding strength of wood veneer (Picea abies) attached between a geopolymer matrixes were investigated by means of a pull-out test. Effects of pre-treatment of wood on the bonding strength were applied whereas a strong influence of pre-treatment on bonding strength could be observed. The treatment of wood veneer showed that using wet veneer (~90% moisture content) leads to the best results compared to untreated dry (~12% moisture content) veneer. Furthermore, the effects of sodium hydroxide extraction and sodium silicate treatment were examined. The lignin UV absorbance values in treated wood, obtained by scanning ultraviolet microspectrophotometry (UMSP), do not show any significant changes in absorbance which mean that there were no complex changes in phenolic wood components, including modification of the lignin side chains. It can be said that the alkaline environment needed for geopolymer was not the main problem that limits wood (Picea abies)-geopolymer compatibility.

Abstract: Many of the complex reinforced Autoclaved Aerated Concrete characteristics under shear and flexure are yet to be identified to employ this material advantageously and economically, as it has many advantages of low weight, fire resistance, acoustic and thermal insulation. It is observed in the article that under two-points loading system, diagonal cracks are usually the first cracks to be observed in the deep beam clear span. The diagonal cracks first are developed in relatively deep beams and the flexural cracks are first developed in shallower beam. The principal mode of failure in the deep beams having adequate reinforcement is diagonal tension cracking. The shear failure is a common type for all beams. This indicates a weak the bond strength between lightweight concrete and reinforcing steel. There are many factors affecting the bond strength between the lightweight concrete and reinforcing steel, where the compressive strength plays an important role in bond strength, and the bond strength is increased by increasing the compressive strength. The AAC beams have the potential to be an excellently energy-saving construction material and is believed to emerge as an alternative to traditional reinforced concrete beam in the near future. This is proved by the experimental analysis.

Abstract: Finite element method (FEM) is employed to study an effect of diffusion bonding strength between aluminium and its copper material and optimized parameters. The diffusion bonding soundness was estimated at different processing parameters such as temperature, pressure and time. The coefficients of linear thermal expansion (CTE) of the metals induce thermal stress at the bonded area. This phenomenon motivated the study of the stress distribution along with maximum and minimum stress values, while bonding of two dissimilar metals at particular bonding process parameters. The incompatible thermal stress at the bonded area plays a vital role in better bond soundness. Thus, it is required to estimate the bonding interface in dissimilar joints. This study was performed using the FEM and the analysis was carried out using the commercial software package Ansys V12.0