Assessment of Tertiary Dendritic Growth and Its Effects on Mechanical Properties of Directionally Solidified Sn-0.7Cu-xAg Solder Alloys

Spinelli, José Eduardo; Silva, Bismarck Luiz; Garcia, Amauri

doi:10.1007/s11664-014-3087-4

Cited by 30 publications

(16 citation statements)

References 29 publications

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“…The −0.55 exponent is recognized as the most appropriate based on a number of experimental evidences in recent studies considering the growth of primary dendrite trunks under transient solidification conditions. 42,43 This kind of experimental law fits well to the experimental scatters of λ 1 and λ 3 obtained for the Sn-34 wt.%Bi alloy. It is worth noting that the theoretical model of Bouchard and Kirkaldy 44 for growth of secondary dendritic arms predicts a −2/3 exponent for λ 2 × V relationships.…”

Section: Sn-52wt%bisupporting

confidence: 78%

Effects of Solidification Thermal Parameters on Microstructure and Mechanical Properties of Sn-Bi Solder Alloys

Silva

Garcia

et al. 2017

Journal of Elec Materi

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Samples extracted along the length of directionally solidified (DS) castings of three Sn-xBi alloys (x = 34 wt.%Bi, 52 wt.%Bi and 58 wt.%Bi) were first evaluated metallographically and then subjected to scanning electron microscopy and energy-dispersive x-ray spectroscopy analyses. The characteristic length scale of both eutectic and dendritic phases forming the microstructure were determined and correlated with solidification thermal parameters (growth rate V, and cooling rate T ˙). Tensile and Vickers hardness tests were performed to allow strength and ductility to be discussed as a function of both microstructure features and alloy solute content. The tertiary dendrite arm spacings along the length of the DS Sn-52 wt.%Bi alloy casting are shown to be lower than those obtained for the Sn-34 wt.%Bi alloy casting. The results of mechanical tests show that, with the decrease in the alloy Bi content, both tensile strength and hardness are improved. This is shown to be mainly attributed to the higher density of Bi precipitates decorating the Sn-rich dendrites, which are finer than the equivalent phase developed for the Sn-52 wt.% Bi alloy. However, the ductility is shown to be significantly improved for specimens associated with regions of more refined microstructure of the Sn-52 wt.%Bi alloy DS casting. A microstructure combining much branched dendrites, fine Bi particles within the β-Sn dendritic matrix and an important proportion of very fine eutectic formed by alternate Bi-rich and Sn-rich phase, seems to be conducive to this higher ductility. In this case, the fracture surface is shown to be more finely broken with presence of dimples for this particular condition, i.e., characteristic of a ductile fracture mode.

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Section: Sn-52wt%bisupporting

confidence: 78%

Effects of Solidification Thermal Parameters on Microstructure and Mechanical Properties of Sn-Bi Solder Alloys

Silva

Garcia

et al. 2017

Journal of Elec Materi

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“…−1/4 and − 1/2 power laws characterize the primary/tertiary and secondary dendrite arm spacings variations with cooling rate and growth rate, respectively. Recent studies with Sn-Zn [33], Sn-Ag and Sn-Bi [21], and Sn-Ag-Cu (SAC) [34] solder alloys considering the growth of dendrite primary trunks as well as the secondary branches under transient solidification conditions reported exponents of − 0.55 and − 2/3, respectively, as being the most appropriate. However, such empirical laws do not represent the behavior of the Sn-52 wt.%Bi alloy examined, as can be seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

Microstructural development and mechanical properties of a near-eutectic directionally solidified Sn–Bi solder alloy

Silva

Reinhart

Nguyen-Thi

et al. 2015

Materials Characterization

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“…In contrast, other research studies with other ternary solder alloys systems focused on change of microstructure due to applied cooling rate. For instance, a single ratio between the cooling rate (Ṫ L ) and the alloy silver content (C 0 -Ag) of 0.45 in Sn-0.7Cu-XAg alloys was shown to be the parametric factor associated with the beginning of the growth of tertiary dendritic branches [15]. Moon and coauthors [16] stated that small Pb additions as 1.0 wt.% to Sn-Bi alloys can drastically expand the freezing range due to the formation of a ternary eutectic at 95.3 °C.…”

Section: Introductionmentioning

confidence: 99%

Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

Silva

Garcia

Spinelli

2016

Materials Characterization

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Assessment of Tertiary Dendritic Growth and Its Effects on Mechanical Properties of Directionally Solidified Sn-0.7Cu-xAg Solder Alloys

Cited by 30 publications

References 29 publications

Effects of Solidification Thermal Parameters on Microstructure and Mechanical Properties of Sn-Bi Solder Alloys

Effects of Solidification Thermal Parameters on Microstructure and Mechanical Properties of Sn-Bi Solder Alloys

Microstructural development and mechanical properties of a near-eutectic directionally solidified Sn–Bi solder alloy

Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

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