Eutectic modification and microstructure development in Al–Si Alloys

Dahle, A. K.; Nogita, Kazuhiro; McDonald, Stuart D.; Dinnis, C. M.; Lu, Lidan

doi:10.1016/j.msea.2005.09.055

Cited by 302 publications

(152 citation statements)

References 17 publications

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“…For example, in modified Al-Si alloys, eutectic grains can nucleate independently and eutectic Al often has a different orientation to the primary Al dendrites [41]. Second, Sn-Sn grain boundaries are often created by eutectic growth (e.g.…”

Section: Tin Grain Structure In Freestanding Solder Ballsmentioning

confidence: 99%

Nucleation and Growth of Tin in Pb-Free Solder Joints

Gourlay

Belyakov

et al. 2015

JOM

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The solidification of Pb-free solder joints is overviewed with a focus on the formation of the Sn grain structure and grain orientations. Three solders commonly used in electronics manufacturing, Sn-3Ag-0.5Cu, Sn-3.5Ag and Sn-0.7Cu-0.05Ni, are used as case studies to demonstrate that growth competition between primary dendrites and eutectic fronts during growth in undercooled melts is important in Pb-free solders, and that a metastable eutectic containing NiSn4 forms in Sn-3.5Ag/Ni joints. Additionally, it is shown that the substrate (metallization) has a strong influence on the nucleation and growth of tin. We identify Co, Pd and Pt substrates as having potential to control solidification and microstructure formation. In the case of Pd and Pt substrates, Sn is shown to nucleate on the PtSn4 or PdSn4 IMC reaction layer at relatively low undercooling of ~4K, even for small solder ball diameters down to <200 m. IntroductionThe transition to Pb-free electronic interconnections has been underway for more than a decade and despite the exemptions to the RoHS Directive there are few applications where Pb-free solders are not being used. At the same time, electronic packaging technologies have been advancing and there is an ongoing need to develop next-generation Pb-free solders and substrates that are better suited to smaller joints that can operate at higher temperature and that are more reliable.The most commonly used Pb-free solders are hypoeutectic or near-eutectic compositions from the Sn-Ag-Cu (SAC), Sn-Ag or Sn-Cu-Ni alloy systems. These compositions solidify with significant differences to the near-eutectic Sn-Pb solders used previously. For example, where the Sn-37Pb

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Section: Tin Grain Structure In Freestanding Solder Ballsmentioning

confidence: 99%

Nucleation and Growth of Tin in Pb-Free Solder Joints

Gourlay

Belyakov

et al. 2015

JOM

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“…These results are in accordance with the results reported by Kaya et al 11 The reduction in hardness observed with addition of Sr could be caused by the effect of Sr on the volume fraction of a-Al in the microstructure. Sr addition causes a shift of the eutectic point to higher Si concentrations and lower temperature 17 and therefore increases the amount of a-Al. Figure 7b shows the variation in hardness as a function of time in the base alloy and the alloy containing combined Co and Ni addition exposed at 240°C.…”

Section: Mechanical Properties: Hardnessmentioning

confidence: 99%

Effect of Co and Ni Addition on the Microstructure and Mechanical Properties at Room and Elevated Temperature of an Al–7%Si Alloy

2017

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Increasing environmental demands are forcing the automotive industry to reduce vehicle emissions by producing more light-weight and fuel efficient vehicles. Al-Si alloys are commonly used in automotive applications because of excellent castability, high thermal conductivity, good wear properties and high strength-to-weight ratio. However, most of the aluminium alloys on the market exhibit significantly reduced strength at temperatures above 200°C. This paper presents results of a study of the effects of Co and Ni in a hypoeutectic Al-Si alloy on microstructure and mechanical properties at room and elevated temperature. Tensile test specimens with microstructures comparable to those obtained in high-pressure die casting, i.e. SDAS * 10 lm, were produced by directional solidification in a Bridgman furnace. The results show an improvement in tensile properties up to 230°C.

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“…Dahle et al [77] compared the development of the cast structure on a macroscopic scale in both unmodified and Sr-modified alloys, see Figure 2.24. Cozonal twinning was present in the silicon fibres in all alloys with twins lying parallel to the apparent growth direction of the fibres.…”

Section: Strontium Modificationmentioning

confidence: 99%

Rheological behavior and microstructural evolution of semi-solid hypereutectic Al-Si-Mg-Cu alloys using rheoforming process /

Tebib¹

2012

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Over the last three decades the semi-solid metal (SSM) processing has received significant attention. Semi-solid processing involves the net shape manufacturing of alloys in the semi-solid state. The principal attraction for the process has been the unique rheology of the slurry which induces better movement of materials through the die and allows intricate thin-wall near net shape components to be cast at lower applied pressures. This behaviour offers considerable advantages to the quality of castings. The reduced oxide entrapment, low porosity and a lower operating temperature make semi-solid processing ideal for the forming of high integrity parts.The aim of the current study was to investigate the rheological behavior and microstructural evolution of hypereutectic Al-Si-Cu and Al-Si-Mg-Cu alloys using conventional and modified SEED process (Swirled Enthalpy Equilibration Device). This project is divided into four parts.

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Eutectic modification and microstructure development in Al–Si Alloys

Cited by 302 publications

References 17 publications

Nucleation and Growth of Tin in Pb-Free Solder Joints

Nucleation and Growth of Tin in Pb-Free Solder Joints

Effect of Co and Ni Addition on the Microstructure and Mechanical Properties at Room and Elevated Temperature of an Al–7%Si Alloy

Rheological behavior and microstructural evolution of semi-solid hypereutectic Al-Si-Mg-Cu alloys using rheoforming process /

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