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The wearout characteristics were investigated for soldered interconnections of surface mount technology (SMT) chip resistors, chip capacitors and a 44 I/O ceramic leaded chip carrier (CLCC) package. Four double‐sided test vehicles were subjected to accelerated thermal cycling in the — 10°C to + 110°C range; 30°C/min ramp rate; and 1 minute dwell time at each temperature extreme. The test was interrupted at initially 500 cycle and later at 1000 cycle intervals to perform visual inspection of all soldered interconnections, functional performance verification for the test vehicles, and resistance measurement on leaded SMT joints. Metallographic examinations and fractographic studies were also performed after 0, 4500 and 13000 cycles to characterise the micromechanisms of soldered joint strength degradation and failure. The wearout thresholds for soldered joints of chip resistors and capacitors on side 1 were respectively 2500 and 4500 cycles. The greater thermal fatigue resistance of the latter joints was attributed to a lower device‐substrate coefficient of thermal expansion (CTE) mismatch and a more favourable device geometry compared with chip resistors. These passive components on side 2, however, showed a virtually identical soldered joint wearout threshold of 6500 cycles. The constraints imposed by the applied mounting adhesive were primarily responsible for this behaviour. No correlation appeared to exist among various failure criteria used to determine the onset of failure for leaded SMT soldered connections. The concurrent monitoring of electrical resistance and the applied tensile load showed a modest relationship between the load drop and resistance increase, however. The test vehicles continued to pass the functional performance verification, even after 13000 thermal cycles. Nonetheless, the joint wearout thresholds were considered to be 2500, 4500 and 4500 cycles for chip resistor, chip capacitor and CLCC components, respectively. A 50% soldered joint strength drop was considered as the wearout threshold for the CLCC device. Metallographic examination showed limited barrel wall cracking of the vias and no evidence of cracks with the through‐hole soldered joints, even after 13000 thermal cycles.

The reliability of solder joints and plated‐through‐hole (PTH) copper structure was investigated for 503 I/O interstitial pin grid array packages with two different pin diameters. Each package type was wave soldered to printed wiring boards having two different surface finishes and PTH sizes, by using the 63Sn–37Pb alloy. Accelerated thermal cycling with continuous monitoring was used in conjunction with metallographic analysis to determine reliability and to elucidate the failure threshold. The microstructural features and failure modes were found to be similar among the solder joints despite the physical differences. The measured solder joint fatigue lifetimes varied from 2450 to 3700 thermal cycles, depending on pin and PTH combinations. The reliability of PTH copper exceeded 4000 thermal cycles regardless of the PTH size. The solder joint fatigue results were used to predict the reliability under operating conditions.

As part of a programme of characterisation of interconnection technologies for computer server products the present investigation was conducted to determine the attachment integrity and long‐term reliability of resistor network ceramic Chip Scale Package (CSP) solder joints. Accelerated thermal cycling with electrical continuity monitoring of the solder joints was used to determine reliability. The thermal cycling was combined with metallographic examination of appropriate solder joints to evaluate the failure modes and to corroborate the failure thresholds. The measured reliability for the CSP solder joints was 1,027 thermal cycles. This implied an estimated minimum lifetime of 7.8 years for the product in a worst‐case field use. The reliability was virtually unaffected by the solder joint pad size and geometry on the board. All fatigue failed solder joints exhibited similar failure modes.

As part of the portable product interconnects characterisation programme, the present investigation was conducted to determine the attachment integrity and long‐term reliability of Thin small Outline package (TSOP) solder joints. Accelerated thermal cycling combined with analytical modelling was used to evaluate the reliability for credit card sized DRAM memory cards. The measured solder joint fatigue lifetimes varied from 645 to 830 thermal cycles for TSOP‐II and I components, respectively. The modelling results corroborated the empirical findings. The solder joint thermal fatigue data were used to predict the card reliability under operating field conditions. The cards were found to be reliable for their intended use environment.

The purpose of this paper is to analyze heat and mass transport mechanism of unsteady MHD thin film flow of aluminium–copper/water hybrid nanofluid influenced by thermophoresis, Brownian motion and radiation.

The authors initially altered the time dependent set of mathematical equations into dimensionless form of equations by using apposite transmutations. These equations are further solved numerically by deploying Runge–Kutta method along with shooting technique.

Plots and tables for skin friction coefficient, Nusselt number, Sherwood number along with velocity, temperature and concentration profiles against pertinent non-dimensional parameters are revealed. The study imparts that aluminium–copper hybrid nanoparticles facilitate higher heat transfer rate compared to mono nanoparticles. It is noteworthy to disclose that an uplift in thermophoresis and Brownian parameter depreciates heat transfer rate, while concentration profiles boost with an increase in thermophoretic parameter.

The current study targets to investigate heat transfer characteristics of an unsteady thin film radiative flow of water-based aluminium and copper hybrid nanofluid. The high thermal and electrical conductivities, low density and corrosion resistant features of aluminium and copper with their wide range of industrial applications like power generation, telecommunication, automobile manufacturing, mordants in leather tanning, etc., have prompted us to instil these particles in the present study.

The present study has many practical implications in the industrial and manufacturing processes working on the phenomena like heat transfer, magnetohydrodynamics, thermal radiation, nanofluids, hybrid nanofluids with special reference to aluminium and copper particles.

To the best extent of the authors’ belief so far no attempt is made to inspect the flow, thermal and mass transfer of water-based hybridized aluminium and copper nanoparticles with Brownian motion and thermophoresis.

Quasi shear and tensile mode stress‐rupture and quasi shear mode creep behaviours were investigated for aged production surface mount soldered connections of 127 mm pitch, rigid gullwing and J‐bend configurations at ambient and 60°C (on limited specimens) environments. These joints were manufactured by the vapour phase reflow soldering process using a 63Sn‐37Pb solder composition. Metallographic examinations and fractrographic studies were also performed on appropriate specimens to characterise the metallurgical attributes of the solder and the joint failure. A relatively coarse solder microstructure was observed with both joint configurations. The steady‐state creep data of both soldered joints exhibited two distinct creep regimes. A grain boundary‐controlled regime at low loads with a slope of 042 for gullwing and 0?50 for J‐bend joints was followed by a dislocation climb‐controlled regime at high loads with a slope of 0?13 and 0?24 for gullwing and J‐bend configurations, respectively. The log‐log plot of applied load varied linearly with rupture time for the entire load range for the respective soldered joints for both modes of testing at room temperature. A transgranular fracture morphology was found to predominate for the entire load regime for the quasi shear mode tested gullwing joints. A mixed‐mode fracture morphology with predominantly transgranular features was observed for both low and high loading conditions for quasi shear mode tested J‐bend specimens. The steady‐state creep elongation in shear showed a strong dependence on the applied load for both types of soldered joints. This was primarily attributed to the presence of relatively large creep transients, especially at higher loads.

An empirical study was conducted to determine the thermal fatigue behaviour of 1.27 mm pitch, J‐bend and gullwing surface mount solder joints, manufactured with four low‐temperature solders. Selected solder alloys were: 58Bi‐42Sn (wt %), 43Sn‐43Pb‐14Bi, 52ln‐48Sn and 40ln‐40Sn‐20Pb. Accelerated thermal cycling was used in conjunction with metallographic analysis and mechanical (pull) strength measurement to test their behaviour. The relative merit of each solder composition was determined by comparing it with 63Sn‐37Pb solder, subjected to identical testing conditions. The strength decreased linearly with increased number of thermal cycles for gullwing solder joints of all four solder alloys. The fatigue lifetime was relatively longer for 58Bi‐42Sn and 40ln‐40Sn‐20Pb than for other alloys, but significantly lower than that obtained with 63Sn‐37Pb solder. No discernible degradation of strength was observed with the J‐bend solder joints of any solder alloy, even after the completion of 6000 thermal cycles. Thermal fatigue resistance of the latter joints was attributed to a more favourable coefficient of thermal expansion (CTE) mismatch. Solder joint cracking occurred only in gullwing components soldered with 52ln‐48Sn, 40ln‐40Sn‐20Pb and 43Sn‐43Pb‐14Bi alloys, after 1000 or 2000 thermal cycles. The crack initiated on the outside surface of the solder fillet, and appeared to propagate through both phases of the microstructure. The stress‐induced heterogeneous coarsening of the microstructure was evident only with 43Sn‐43Pb‐14Bi solder, although not as prevalent as that usually observed with eutectic Sn‐Pb solder. Fatigue cracks were absent from solder joints of 58Bi‐42Sn and 63Sn‐37Pb alloys.

This paper aims to study the impacts of viscous dissipation, thermal radiation and Joule heating on squeezing flow current and the heat transfer mechanism for a magnetohydrodynamic (MHD) nanofluid flow in parallel disks during a suction/blowing process.

First, the governing momentum/energy equations are transformed into a non-dimensional form and then the obtained equations are solved by modified Adomian decomposition method (ADM), known as Duan–Rach approach (DRA).

The effect of the radiation parameter, suction/blowing parameter, magnetic parameter, squeezing number and nanoparticles concentration on the heat transfer and flow field are investigated in the results. The results show that the fluid velocity increases with increasing suction parameter, while the temperature profile decreases with increasing suction parameter.

A complete analysis of the MHD fluid squeezed between two parallel disks by considering Joule heating, thermal radiation and adding different nanoparticles using the novel method called DRA is addressed.

The purpose of this research is to describe the importance of the Cattaneo–Christov theory of heat conduction in a triangular enclosure with a semi-circular heater. Analysis subjected to Fe₃O₄-H₂O nanofluid is reported. Viscosity dependent on magnetic field is taken into consideration to simulate ferrofluid viscosity. Besides, heat generation and shape factor of nanoparticles are also considered.

The well-known control volume finite element method is used for simulations.

The outcomes reveal that the magnetic field can be introduced to the system as a controlling element.

No such analysis exists in the literature.