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Eutectic Sn‐Ag solder is being considered as a potential replacement for Sn‐Pb solders. A potential drawback to using the eutectic Sn‐Ag solder is its higher melting point, 221°C, compared with the eutectic Pb‐Sn solder. Owing to its higher melting temperature, the eutectic Sn‐Ag solder is also being considered for automotive under‐the‐hood applications, which experience high temperature environments. Electronic components and/or circuit boards are often coated with Pb‐bearing solder to facilitate soldering operations. Soldering Pb‐bearing solder coated components and/or boards with eutectic Sn‐Ag solder will result in joints contaminated with Pb. In this study, the effects of Pb contamination on eutectic Sn‐Ag solder joints were investigated using three ternary alloys made by incorporating some Pb into eutectic Sn‐Ag solder. These ternary alloys all showed a peak at 178°C in heating curves obtained using Differential Scanning Calorimetry (DSC), which resulted from the ternary eutectic composition in the Sn‐Ag‐Pb system. The Pb phases in the ternary alloys were found to be dispersed throughout the microstructure. A practical implication of Pb contamination in eutectic Sn‐Ag solder joints is that the service temperature of such joints would be limited by the lower melting temperature of the ternary eutectic phase.

According to the microstructural characteristics of composite ceramic, the strain field distribution regularity of triangular symmetrical composite eutectic is obtained from the stress field distribution regularity of three-phase element in composite ceramic. In allusion to the damage of composite eutectic, it is introduced as a variable in this paper with the aim to determine the strain field distribution regularity of triangular symmetrical composite eutectic with damage behavior.

On the basis of the relationship between strain field and fiber inclusions volume fraction, the strain field of composite eutectic is analyzed.

The strain field of composite ceramic is distinctly dependent on the fiber inclusions volume fraction, fiber diameter and damage behavior of composite eutectic by quantitative analysis. The strain in matrix parallel to eutectic is the maximum linear strain and the main factor for the damage and fracture of eutectics.

The foundation of the strength research of composite eutectic is laid.

Composite ceramic has the excellent properties at normal and high temperatures, especially when the structure of the composite eutectic is triangular symmetrical. Obviously, mechanical behavior and fracture properties of composite ceramic closely relates to the micro-structure of symmetrical triangular eutectic. In order to reveal the mechanical properties of eutectic composite ceramic, it is necessary to determine the intrinsic strength of triangular composite eutectic. Since the fiber and matrix of triangular symmetrical composite eutectic sharing a same covalent bond, the theoretical cohesion strength of symmetrical triangular eutectic was obtained by the combination-separation displacement of intrinsic bond. Basing on micro-structure plastic deformation before fracture of composite eutectic matrix, the dislocation pile-up model of eutectic composite ceramics was established. And then intrinsic bond fracture shear stress of triangular symmetrical composite eutectic was given by using the theory of dislocation pile-up. According to the macroscopic structure properties of triangular symmetrical composite eutectic and the distribution of stress field of composite eutectic, intrinsic strength of eutectic was obtained. The results shows that intrinsic strength of triangular symmetrical composite eutectic possessed clear size-dependence and the stress decreases with the increases of the diameter of fiber inclusions.

South Africa is the highest consumer of commercial energy per capita in Africa, ranking 16th in the world for primary energy consumption. It is also ranked among the bottom 50 of the 150 countries regarding energy efficiency. The cold chain is a large contributor through refrigerated transport vehicles. To comply with the changing climate regulations, cryogenic and eutectic systems are systems with great potential for small distance refrigerated transport. The purpose of this paper is to introduce eutectic system to medium distance refrigerated transport.

This study presents the potential use of Eutectic plates inside a medium refrigerated transport vehicle, by numerically investigating the characteristics of phase change material eutectic plates applied at low-temperature ranges. A physical model and a mathematical model for three-dimensional transient natural flow were developed as proposed by Xiaofeng and Zhang. Using the governing equation of mass, momentum and energy conservation, three Eutectic plate configurations were modeled and simulated in ANSYS Fluent for 5 h.

A uniform heat transfer and airflow condition inside a refrigerated compartment were predicted using the Reynolds stress model. The configuration with eutectic plates placed at the top and side showed great potential for the system functioning in the South African climate.

Medium refrigerated transport vehicle.

This configuration had a high-temperature distribution across the compartment and promoted high air circulations, showing that it could be ideal for medium refrigerated transport vehicles delivering perishable foodstuffs or non-food goods.

This paper reviews the status of lead‐free solder development works. Some of the solder systems — Bi‐Sn, Bi‐Sn‐Fe, ln‐Sn, Sn, Sn‐Ag, Sn‐Ag‐Zn, Sn‐Ag‐Zn‐Cu, Sn‐Bi‐Ag, Sn‐Cu, Sn‐Cu‐Ag, Sn‐In‐Ag, Sn‐Sb, Sn‐Zn and Sn‐Zn‐ln — are discussed in more detail, while others are briefly commented on. In general, compared with eutectic Sn‐Pb solder, all the lead‐free solder alternatives investigated more or less exhibit some shortcomings, such as price, physical, metallurgical or mechanical properties. Relatively, Sn‐ln‐containing systems are more promising in terms of solder mechanical properties and soldering performance, although the price of ln may be a concern. Eutectic Sn‐Ag solder doped with Zn, Cu or Sb exhibits good mechanical strength and creep resistance, due to refined microstructure. The Bi‐Sn systems doped with other elements may have a niche in the low temperature soldering field. Eutectic Sn‐Cu has good potential due to its good fatigue resistance. The eutectic Sn‐Zn system modified with ln and/or Ag may be promising in terms of mechanical properties. Finding a lead‐free alternative for high temperature solders presents the biggest challenge to the industry.

A study was performed to develop a different experimental methodology to assess wettabilities of solders on various printed wiring board (PWB) finishes, based on a modified spreading test in which solder pastes were heated following temperature reflow profiles representative of those used in surface mount technology (SMT) instead of using a fixed rate temperature ramp. Three solder alloys (Sn63‐Pb37, Sn96.5‐Ag3.5, and CASTIN^TM: Sn96.2‐Ag2.5‐Cu0.8‐Sb0.5), two fluxes (rosin, mildly activated, RMA, and no‐clean, NC), and seven PWB finishes (Pd, Au/Ni, Ni, Ag, Sn, and organic solderability preservatives: OSP), and bare copper were involved in the study. Better wettabilities were observed in the current study than the results reported in the literature for conventional tests on the same combination of solder alloy, flux, and substrate. The different results in measurement of wettabilities obtained in the current study were attributed to the more adequate heating process allowing flux activation, which reduced reoxidation of solder powders and substrates during the reflow process and thus improved wettabilities of solders. Compared to the results obtained from the popular wetting balance test, the current study demonstrated a more realistic simulation of, and approach to, assessing the wettability of solder for SMT.

This paper discusses the microstructures of solder joints and the mechanism of thermal fatigue, which is an important source of failure in electronic devices. The solder joints studied were near‐eutectic Pb‐Sn solder contacts on copper. The microstructure of the joints is described. While the fatigue life of near‐eutectic solder joints is strongly dependent on the operating conditions and on the microstructure of the joint, the metallurgical mechanisms of failure are surprisingly constant. When the cyclic load is in shear at temperatures above room temperature the shear strain is inhomogeneous, and induces a rapid coarsening of the eutectic microstructure that concentrates the deformation in well‐defined bands parallel to the joint interface. Fatigue cracks propagate along the Sn‐Sn grain boundaries and join across the Pb‐rich regions to cause ultimate failure. The failure occurs through the bulk solder unless the joint is so thin that the intermetallic layer at the interface is a significant fraction of the joint thickness, in which case failure may be accelerated by cracking through the intermetallic layer. The coarsening and subsequent failure are influenced more strongly by the number of thermal cycles than by the time of exposure to high temperature, at least for hold times up to one hour. Thermal fatigue in tension does not cause well‐defined coarsened bands, but often leads to rapid failure through cracking of the brittle intermetallic layer. Implications are drawn for the design of accelerated fatigue tests and the development of new solders with exceptional fatigue resistance.

The final properties of ductile iron are decided by the inoculant processing while pouring the melt. The shape and size of nodules generated during solidification are of paramount importance in solidification of ductile cast iron. The purpose of this study is to examine the effect of different inoculant addition on the solidification of ductile cast iron melt through thermal analysis.

Thermal analysis has recently grown as a tool for modeling the solidification behavior of ductile cast irons. Iron properties will be predicted by analyzing the cooling curve patterns of the melts and predicting the related effectiveness of inoculant processing. In this study, thermal analysis is used to evaluate the need for inoculation.

The amount and type of inoculation will affect the amount of undercooling during the solidification of ductile cast iron. It is found that the addition of 0.1 to 0.4 Wt.% inoculant lowers the austenite dendrite formation starting temperature while increasing the eutectic freezing temperature. Microstructure analysis revealed that the addition of inoculation increases the nodule count from 103 to 242 nodules. The beneficial effects of inoculation are sustained by an improved graphitization factor, which shows the formation of graphite nodules in the second phase of the eutectic reaction.

The inoculation treatment has improved metallurgical occurrences such as carbide to graphite conversion, graphite microstructure control, graphite nodule count at the start of solidification and the last stage of solidification, which determines the soundness of casting. The foundry industry can follow these steps for monitoring the solidification of ductile iron castings.

Reports the research and development results on flip chip on FR‐4 and ceramics, using anisotropic conductive film (ACF), anisotropic conductive paste (ACP), or eutectic solder with underfill. Several types of ACF and ACP with different types of conductive particles and adhesives were investigated. Simple but high yield procedures for reworking flip chip on board using ACP and ACF were developed. Processes for flip chip on FR‐4 and ceramic boards using eutectic solder bumps with underfill were also evaluated. The flip chips were assembled on test vehicles for temperature cycling and high‐temperature high‐humidity tests. The reliability performance of the three processes (gold bumps with ACF, gold bumps with ACP, and eutectic solder bumps with underfill) is compared.

The purpose of this paper is to study the wear behaviour of eutectic and hypoeutectic Al‐Si‐Mg‐Ce alloys.

The eutectic and hypoeutectic alloys were prepared using permanent mould casting process by varied cerium (Ce) addition in the alloy from 1 to 3 wt%. Dry sliding wear tests were performed against a hardened carbon steel (Fe‐2.3%Cr‐0.9%C) using a pin‐on‐disc configuration with fixed sliding speed of 1 m/s and load 50 N at room temperature of ∼25 degree. Morphologies of both worn surfaces and collected debris were characterised by a scanning electron microscope (SEM) equipped with an energy dispersive X‐ray spectrometer (EDS).

It was revealed that following the addition of cerium, intermetallic Al4Ce needle‐like structure was present in eutectic alloys whereas CeMg2Si2 blocky phase was present in the hypoeutectic alloys. The increasing of Ce addition up to 3.0 wt% in hypoeutectic alloy led to formation of AlCe3 intermetallic phase. The increase in cerium content up to 2 wt% led to higher wear resistance behaviour for both as‐cast alloys. Formation of craters and localised plastic deformation were observed on the worn surface of both as‐cast alloys, resulting fine particulate and sheet‐like wear debris. The wear resistance was found to be higher for hypoeutectic alloy compared to the eutectic alloy containing Ce.

An attempt has been made to study the influence of intermetallic compound containing Ce in the Al‐Si‐Mg alloys on wear behaviour of both as‐cast alloys.