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Article
Publication date: 6 April 2012

Xin Li, Gang Chen, Xu Chen, Guo‐Quan Lu, Lei Wang and Yun‐Hui Mei

The purpose of this paper is to evaluate the mechanical properties of nano‐silver paste sintered lap shear structures and to discuss the effects of loading rate and ambient…

Abstract

Purpose

The purpose of this paper is to evaluate the mechanical properties of nano‐silver paste sintered lap shear structures and to discuss the effects of loading rate and ambient temperature on shear strength and fracture mechanism.

Design/methodology/approach

Single lap shear joints with an area of 2 mm2 and thickness of 50 μm were fabricated by joining two copper substrates with nano‐silver paste. The lap shear tests were carried out under strain control mode on a micro uniaxial fatigue testing system with four loading rates and temperatures. The fracture sections were analyzed by SEM observation to determine the effect of temperature on the fracture mechanism.

Findings

Results from the study highlighted that the shear strain rate and temperature can have a significant impact on the shear behaviour of nano‐silver paste sintered lap shear joints. The shear strength increased with shear strain rate, but decreased with increasing ambient temperature. The lap shear joints displayed excellent ductility at higher temperatures due to the grain plastic flow.

Originality/value

So far, the investigation of the mechanical behaviour of low‐temperature sintered nano‐silver paste was restricted to a film form. No work had been done on nano‐silver paste connected structures. The findings presented in this paper give a basic understanding of the mechanical properties of nano‐silver sintered joints when sheared under different loading rates and temperatures.

Article
Publication date: 18 April 2019

Isam Tareq Abdullah and Sabah Khammass Hussein

The purpose of this paper is to join a sheet of the AA7075 with the high-density polyethylene (HDPE) by a lap joint using friction spot processing and investigate the temperature…

Abstract

Purpose

The purpose of this paper is to join a sheet of the AA7075 with the high-density polyethylene (HDPE) by a lap joint using friction spot processing and investigate the temperature distribution of joint during this process using the finite element method (FEM).

Design/methodology/approach

A semi-conical hole was manufactured in the AA7075 specimen and a lap joint configuration was prepared with the HDPE specimen. A rotating tool was used to generate the required heat to melt the polymer by the friction with the AA7075 specimen. The applied tool force moved the molten polymer through the hole. Four parameters were used: lower diameter of hole, rotating speed, plunging depth and time. The results of shear test were analyzed using the Taguchi method. A FEM was presented to estimate the temperature distribution of joint during the process.

Findings

All specimens failed by shearing the polymer at the lap joint region without dislocation. The specimens of the smallest diameter exhibited the highest shear strength at the lap joint. The maximum ranges of temperature were recorded at the contact region between the rotating tool and the AA7075 specimen. The tool plunging depth recorded the highest effect on the generated heat compared with the rotating speed and plunging time.

Originality/value

For the first time, the AA7075 sheet was joined with the HDPE sheet by friction spot processing. The temperature distribution of this joint was simulated using the FEM.

Details

International Journal of Structural Integrity, vol. 10 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 December 2002

Richard Ludwig, Ning‐Cheng Lee, Chonglun Fan and Yun Zhang

Two new electrolytically plated lead‐free surface finishes are evaluated for their wettability, bond strength, and voiding performance, and are compared with electrolytic nickel…

Abstract

Two new electrolytically plated lead‐free surface finishes are evaluated for their wettability, bond strength, and voiding performance, and are compared with electrolytic nickel gold and an OSP. The results indicate that Ni–Sn achieve the highest wettability, one of the highest lap shear strengths, and the lowest levels of voiding. It also performs better under a long reflow profile. Under most instances, the soldering performance is comparable with, or better than, the reference OSP and Ni–Au surface finishes. Ni–PdCo–Au was found to give a poor wettability, fairly low lap shear strength, and have high levels of voiding. However, it is fairly stable, and its soldering performance is not sensitive to the reflow profile length or atmosphere, aging treatment, or flux chemistry. OSP was found to be the poorest in terms of wettability, but one of the best for lap shear strength. It also performs best under long profile, is not sensitive to reflow atmosphere, is slightly sensitive to alloy type, but is very sensitive to aging and flux chemistry.

Details

Soldering & Surface Mount Technology, vol. 14 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 4 May 2023

Muhammad Asyraf Abdullah and Siti Rabiatull Aisha Idris

Pb-free solders have been developed to replace the standard Sn–Pb eutectic solder since the prohibition on Pb used in solders. The Sn–Ag–Cu series of lead-free solders is the most…

Abstract

Purpose

Pb-free solders have been developed to replace the standard Sn–Pb eutectic solder since the prohibition on Pb used in solders. The Sn–Ag–Cu series of lead-free solders is the most extensively used in the electronics industry. The Ag3Sn, which forms during isothermal ageing, can significantly degrade solder joint reliability. Sn–Ag–Cu solder’s high price further hindered its use in the electronics industry. This paper aims to investigate different copper percentages into Sn–xCu solder alloy to improve its microstructure and strength performance.

Design/methodology/approach

The solder alloys used in this work were Sn–xCu, where x = 0.0, 0.3, 0.5, 0.7, 1.0 Wt.%, which was soldered onto electroless nickel immersion gold (ENIG) substrate using carbon dioxide (CO2) gas laser. Then these samples were subjected to isothermal aging for 0, 200, 500, 1,000 and 2,000 h. The Sn–xCu solder alloy was fabricated through a powder metallurgy process.

Findings

Microstructure characterization showed that Cu addition resulted in fine and rounded shape of Cu–Sn–Ni particles. Shear strength of Sn–xCu solder joints was increased with increasing Cu content, but at aging duration of 1,000 h, it dropped slightly. It is believed that the strength improved due to the increment of diffusion rate during isothermal aging.

Practical implications

In a Cu–Sn solder, the recommended amount is 1.0 Wt.% of Cu. In extensive aging procedures, it was discovered that Sn1.0Cu solder improved the reliability of solder joints. The findings indicated that the innovative solder alloys might satisfy the needs of high-reliability applications.

Originality/value

The study shows that the right amount of Cu enhances the solidification of Sn–Cu solder, increasing the shear force of the Cu–Sn solder joint. The Sn1.0Cu exhibits a ductile fracture on the top microstructure, improving the joint’s average shear strength.

Details

Soldering & Surface Mount Technology, vol. 35 no. 4
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 1 January 1989

L.M. Leung and K.K.T. Chung

Traditional B‐staged epoxy film adhesives have been used as substrate attach adhesive for hybrid circuits. The advantages of using film adhesive instead of paste adhesive are…

Abstract

Traditional B‐staged epoxy film adhesives have been used as substrate attach adhesive for hybrid circuits. The advantages of using film adhesive instead of paste adhesive are precise bond‐line, clean operation, ease of application for larger bonding area and possibility to automate the process for large volume production. Epoxy, in general, is more stable than polyurethane and is better in adhesion with no contamination problems in comparison with silicone. Traditional epoxy, however, has high bond strength and is therefore limited only to substrates with matched thermal expansion properties. Combining the advantages of excellent adhesion of epoxy and flexibility of rubbery substance, a low glass transition temperature (Tg) epoxy which is flexible in nature has been developed for bonding substrates with mis‐matched thermal expansion coefficient. The new epoxy adhesive is also designed to meet the requirements of MIL‐STD‐883C/5011 in application without sacrificing ionic purity, low outgassing, thermal conductivity and long‐term dielectric or conductive properties. The new flexible film adhesive, in both its insulating and conductive forms, has attracted new applications and designs that were not previously feasible. For example, the flexible film adhesive can be used to bond ceramic hybrids directly to a lower cost metal substrate such as aluminium or copper. Testing has been performed by users on the combination of alumina/aluminium for over 1000 thermal cyclings and shocks from −55 to 150°C for large area bonding (up to a maximum of 6 x 6 inches square). The cured flexible epoxy adhesive, while very pliable, also exhibits more than 1,000 to 2,000 psi lapshear strength (depending on the type of substrate) and withstands more than 15,000 g acceleration test.

Details

Microelectronics International, vol. 6 no. 1
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 6 April 2020

Salim Çam and Adnan Özel

This study aims to investigate the effect of opposing notches formed on the adherends on the tensile strength of an adhesively bonded single-lap joint.

Abstract

Purpose

This study aims to investigate the effect of opposing notches formed on the adherends on the tensile strength of an adhesively bonded single-lap joint.

Design/methodology/approach

Different notch geometries were constructed on adherends and evaluated by using the Taguchi method to obtain optimum notch geometry. Then finite element analysis was conducted considering optimum notch geometries by using the cohesive zone model. Lastly, finite element analysis results were validated experimentally.

Findings

Experimental and numerical studies revealed that notches formed on adherends increased the tensile strength of the joint. The failure load of the Type-III joint, where the highest increase was observed, increased by 15 per cent. In addition, it was found that the notch shape, length, depth and distance to the overlap area had significant effects on the failure load of the joint.

Originality/value

This study shows that higher joint strengths can be accomplished by using the same joint configuration by notching adherends.

Details

Engineering Computations, vol. 37 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 6 June 2016

Hardinnawirda Kahar, Zetty Akhtar Abd Malek, Siti Rabiatull Aisha Idris and Mahadzir Ishak

This paper aims to study the effect of aging and cooling rate on the reliability of the solder joint using electroless nickel boron (EN-Boron) as a surface finish in the…

Abstract

Purpose

This paper aims to study the effect of aging and cooling rate on the reliability of the solder joint using electroless nickel boron (EN-Boron) as a surface finish in the electronic packaging area.

Design/methodology/approach

EN-Boron was plated on a Cu substrate through electroless plating method. This process was followed by reflow soldering of Sn–3.0Ag–0.5Cu solder alloy on metallized Cu substrate to form a joining. Then, the specimens were cooled using different cooling mediums such as air (slow cooling) with 15.7 °C/min and water (fast cooling) with 110.5 °C/min. After that, the specimens were subjected to isothermal aging at 150°C for 0, 250 and 1,000 h. Finally, they went through a lap shear test following ASTM D1002. Optical microscope and scanning electron microscopy were used for intermetallic compound (IMC) characterization. The type of IMC formed was confirmed by field emission scanning electron microscope-energy-dispersive X-ray spectroscopy (FESEM-EDX).

Findings

The results showed that the IMC type changed from the combination of Ni3Sn4 and (Ni, Cu)3Sn4 after reflow soldering into fully (Ni, Cu)3Sn4 when aged for 1,000 h. The formation of (Ni, Cu)3Sn4 and Cu3Sn underneath the IMC layer played a role in reducing the shear strength of joining. Overall, water cooling was reported to provide higher shear strength of solder joint compared to air cooling medium.

Originality/value

The shear strength when using EN-Boron as the surface finish is comparable to the surface finish conventionally used.

Details

Soldering & Surface Mount Technology, vol. 28 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 18 January 2024

Uğur Kemiklioğlu, Sermet Demir and Caner Yüksel

Adhesively bonded joints are used in many fields, especially in the automotive, marine, aviation, defense and outdoor industries. Adhesive bonding offers advantages over…

Abstract

Purpose

Adhesively bonded joints are used in many fields, especially in the automotive, marine, aviation, defense and outdoor industries. Adhesive bonding offers advantages over traditional mechanical methods, including the ability to join diverse materials, even load distribution and efficient thermal-electrical insulation. This study aims to investigate the mechanical properties of adhesively bonded joints, focusing on adherends produced with auxetic and flat surfaces adhered with varying adhesive thicknesses.

Design/methodology/approach

The research uses three-dimensional (3D)-printed materials, polyethylene terephthalate glycol and polylactic acid, and two adhesive types with ductile and brittle properties for single lap joints, analyzing their mechanical performance through tensile testing. The adhesion region of one of these adherends was formed with a flat surface and the other with an auxetic surface. Adhesively bonded joints were produced with 0.2, 0.3 and 0.4 mm bonding thickness.

Findings

Results reveal that auxetic adherends exhibit higher strength compared to flat surfaces. Interestingly, the strength of ductile adhesives in auxetic bonded joints increases with adhesive thickness, while brittle adhesive strength decreases with thicker auxetic bonds. Moreover, the auxetic structure displays reduced elongation under comparable force.

Originality/value

The findings emphasize the intricate interplay between adhesive type, bonded surface configuration of adherend and bonding thickness, crucial for understanding the mechanical behavior of adhesively bonded joints in the context of 3D-printed materials.

Details

Rapid Prototyping Journal, vol. 30 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 February 2005

B.C. Samanta, T. Maity, S. Kar and A.K. Banthia

To evaluate the efficiency of modifying epoxy resin using amine terminated poly(ethylene glycol) benzoate (ATPEGB) for improved toughness and to optimise the results of such a…

1228

Abstract

Purpose

To evaluate the efficiency of modifying epoxy resin using amine terminated poly(ethylene glycol) benzoate (ATPEGB) for improved toughness and to optimise the results of such a modification.

Design/methodology/approach

For effective toughening, various compositions were made by incorporating different concentrations of ATPEGB. The impact and adhesive strengths of the unmodified and modified epoxy networks were characterised.

Findings

The modification of epoxy resin using ATPEGB showed significant enhancement of impact and adhesive strengths over the unmodified one. The modification caused a chemical linkage between ATPEGB and resin which led not only to a phase separation but also to ensuring the intrinsically strong chemical bonds across the ATPEGB phase/resin matrix interface, which was the main cause to the improved impact and adhesive strengths. The optimum results were obtained at 12.5 phr (parts per hundred parts of epoxy resin) of modifier.

Research limitations/implications

The modifier, ATPEGB, used in the present context was synthesised from poly(ethylene glycol) (PEG) of molecular weight 600. Besides, it could be synthesised from PEG of molecular weight 200, 400, 4,000, 20,000 etc. In addition, the efficiency of modification of epoxy resin using these could also be studied.

Practical implications

The method developed provided a simple and practical solution to improving the toughness of cured epoxy.

Originality/value

The method for enhanced toughness of cured epoxy was novel and could find numerous applications in surface coating and adhesive.

Details

Pigment & Resin Technology, vol. 34 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 March 2013

G. Gkikas, A. Paipetis, A. Lekatou, N.M. Barkoula, D. Sioulas, B. Canflanca and S. Florez

Bonded composite patches are ideal for aircraft structural repair as they offer enhanced specific properties, case‐tailored performance and excellent corrosion resistance. Bonding…

Abstract

Purpose

Bonded composite patches are ideal for aircraft structural repair as they offer enhanced specific properties, case‐tailored performance and excellent corrosion resistance. Bonding minimizes induced stress concentrations unlike mechanical fastening, whilst it seals the interface between the substrate and the patch and reduces the risk of fretting fatigue that could occur in the contact zone. The purpose of this paper is to assess the electrochemical corrosion performance and the environmentally induced mechanical degradation of aerospace epoxy adhesives when carbon nanotubes (CNTs) are used as an additive to the neat epoxy adhesive.

Design/methodology/approach

The galvanic effect between aluminium substrates and either plain or CNT enhanced carbon fibre composites, was measured using a standard galvanic cell. Also, rest potential measurements and cyclic polarizations were carried out for each of the studied systems. The effect of the CNT introduction to a carbon fiber reinforced plastic (CFRP) on the adhesion efficiency, before and after salt‐spraying for 10, 20 and 30 days, was studied. The adhesion efficiency was evaluated by the single lap joint test.

Findings

The corrosion behaviour of the system is polymer matrix type dependent. CNT introduction to a CFRP may induce small scale localized degradation.

Originality/value

This paper fulfills an identified need to study how the shear strength and the response to galvanic corrosion are affected by epoxy resins modified by carbon nanotubes.

Details

International Journal of Structural Integrity, vol. 4 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

1 – 10 of 420