<i>In situ</i> study on secondary dendrite arm coarsening of Sn–Bi alloy by synchrotron microradiography

Xu, Jun; Wang, T M; Zhu, Jing; Xie, Honglan; Xiao, Tiqiao; Li, T J

doi:10.1179/143307511x12998222919155

Cited by 8 publications

(5 citation statements)

References 10 publications

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“…The average secondary dendrite arm spacing (SDAS) changes with different heat fluxes are plotted in Figure 9b, and the average SDAS keeps increasing with heat flux, changing from large heat extraction to large heat input. A similar effect has been reported during the secondary dendrite arm coarsening in Sn-Bi alloy by means of synchrotron microradiography [29]. In order to understand the relations between temperature and solute segregation inside the interface during phase transition, we plot the temperature and concentration distributions along the central vertical lines at t = 2 ms with different values of boundary heat flux in Figure 10.…”

Section: Effect Of Different Magnitudes Of Heat Fluxsupporting

confidence: 65%

Phase field simulation of dendrite growth with boundary heat flux

Zhang

2014

Integr Mater Manuf Innov

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Boundary heat flux has a significant effect on solidification behavior and microstructure formation, for it can directly affect the interfacial heat flux and cooling rate during phase transition. In this study, a phase field model for non-isothermal solidification in binary alloys is employed to simulate the free dendrite growth in undercooled melts with induced boundary heat flux, and an anti-trapping current is introduced to suppress the solute trapping due to the larger interface width used in simulations than a real solidifying material. The effect of heat flux input/extraction from different boundaries was studied first. With heat input from boundaries, the temperature can be raised and the dendritic morphology changed with gradient temperature distribution caused by the heat flux input coupling with latent heat release during the liquid-solid phase transition. Also, the concentration distribution can be also influenced by this irregular temperature distribution. Heat flux extraction from the boundaries can decrease the temperature, which results in rapid solidification with small solute segregation and concentration changes in the dendrite structures. Also, dendrite growth manner changes caused by undercooling variation, the result of competition between heat flux and latent heat release from phase transition, are also studied. Results indicate that heat flux in the simulation zone significantly reduces the undercooling, thus slowing down the dendrite formation and enhancing the solute segregation, while large heat extraction can enlarge the undercooling and lead to rapid solidification with large dendrite tip speed and small secondary dendrite arm spacing, while solute segregation tends to be steady. Therefore, the boundary heat flux coupling with the latent heat release from the solidification has an effective influence on the temperature gradient distribution within the simulation zone, which leads to the morphology and concentration changes in the dendritic structure formation.

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Section: Effect Of Different Magnitudes Of Heat Fluxsupporting

confidence: 65%

Phase field simulation of dendrite growth with boundary heat flux

Zhang

2014

Integr Mater Manuf Innov

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“…Several sets of results from the literature and unidirectional solidification experiments carried out in the present study providing information on microstructures of Sn-Bi and Sn-Cu alloys allowed the coupled zones of these alloys systems to be determined. The derived solidification selection maps 9) Sn-Bi alloys-related studies (Shen et al, 2019;Gibbs et al, 2016;Zhang et al, 2015;Gusakova et al, 2014;Wang et al, 2014;Xiaowu et al, 2012;Xu et al, 2011Xu et al, , Çadırlı et al, 2009Braga et al, 2007) considering the coupled zone concept permitted the importance of the thermal gradient, G, to be simultaneously evaluated with the solidification velocity, v, in the definition of the resulting microstructure, as for transient solidification conditions, G and v cannot be dissociated. This microstructure-processing mapping approach appears to be promising to predict phase competition in the use of Sn-Cu and Sn-Bi alloys as soldering materials, as a close manipulation of the microstructure is considered of utmost importance for the metallurgical quality of the product.…”

Section: Discussionmentioning

confidence: 99%

“…To research specific microstructures related to given alloy compositions and processing conditions of Sn-Cu and Sn-Bi alloys, a lot of researches have examined the structure/ interface evolution during solidification through expressing solidification (interface) velocity, v, and temperature gradient, G (Esaka et al, 2015;Ventura et al, 2011Ventura et al, , Çadırlı et al, 2010Ventura et al, , Çadırlı et al, 2009Machida et al, 2006;Shen et al, 2019;Gibbs et al, 2016;Zhang et al, 2015;Gusakova et al, 2014;Wang et al, 2014;Xiaowu et al, 2012;Xu et al, 2011Xu et al, , Çadırlı et al, 2009Braga et al, 2007). Each of these studies is limited to a certain range of compositions and a set of solidification velocities, usually carried out with a fixed value of G. Kurz (2001) demonstrated the importance of implementing a combination of microstructure x process mappings.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 4 Projections of (a) cooling rate and (b) solidification velocity (black circles, squares and open stars) in addition to data from nine (9) Sn-Bi alloys-related studies(Shen et al, 2019;Gibbs et al, 2016;Zhang et al, 2015;Gusakova et al, 2014;Wang et al, 2014;Xiaowu et al, 2012;Xu et al, 2011 Xu et al, , Çadırlı et al, 2009Braga et al, 2007) considering the coupled zone concept…”

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confidence: 99%

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Local solidification thermal parameters affecting the eutectic extent in Sn-Cu and Sn-Bi solder alloys

Kakitani

Silva

et al. 2021

SSMT

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Purpose Overall, selection maps about the extent of the eutectic growth projects the solidification velocities leading to given microstructures. This is because of limitations of most of the set of results when obtained for single thermal gradients within the experimental spectrum. In these cases, associations only with the solidification velocity could give the false impression that reaching a given velocity would be enough to reproduce a result. However, that velocity must necessarily be accompanied by a specific thermal gradient during transient solidification. Therefore, the purpose of this paper is to not only project velocity but also include the gradients acting for each velocity. Design/methodology/approach Compilation of solidification velocity, v, thermal gradient, G, and cooling rate, Ṫ, data for Sn-Cu and Sn-Bi solder alloys of interest is presented. These data are placed in the form of coupled growth zones according to the correlated microstructures in the literature. In addition, results generated in this work for Sn-(0.5, 0.7, 2.0, 2.8)% Cu and Sn-(34, 52, 58)% Bi alloys solidified under non-stationary conditions are added. Findings When analyzing the cooling rate (Ṫ = G.v) and velocity separately, in or around the eutectic composition, a consensus cannot be reached on the resulting microstructure. The (v vs. G) + cooling rate diagrams allow comprehensive analyzes of the combined v and G effects on the subsequent microstructure of the Sn-Cu and Sn-Bi alloys. Originality/value The present paper is devoted to the establishment of (v vs. G) + cooling rate diagrams. These plots may allow comprehensive analyses of the combined v and G effects on the subsequent microstructure of the Sn-Cu and Sn-Bi alloys. This microstructure-processing mapping approach is promising to predict phase competition and resulting microstructures in soldering of Sn-Cu and Sn-Bi alloys. These two classes of alloys are of interest to the soldering industry, whereas manipulation of their microstructures is considered of utmost importance for the metallurgical quality of the product.

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“…Thus mechanism A depends on secondary arm coarsening, a phenomenon which occurs during the early stages of solidification and which starts earlier, i.e. at higher temperature when the cooling rate is divided by a factor 2, see [33].…”

Section: Effect Of Cooling Rate On Pore Nucleationmentioning

confidence: 99%

Tracking pores during solidification of a Ni-based superalloy using 4D synchrotron microtomography

et al. 2019

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Time-resolved in situ microtomography is employed to track the nucleation and growth of individual pores during solidification of a commercial nickel-based superalloy. Three cooling rates (0.1, 0.5 and 1°C/s) are investigated to evaluate the effect of this key processing parameter on the formation of porosity. Phase contrast obtained with a coherent X-ray beam is used to visualize the evolution of dendritic structures in absence of a sufficient absorption contrast. Two mechanisms leading to shrinkage pores have been identified. The first mechanism (mechanism A) is associated with the coalescence of secondary dendrite arms at temperature during the early stages of solidification. The second mechanism (mechanism B) is related to insufficient liquid feeding in the interdendritic region during the last stages of solidification, at lower temperatures. A variation of cooling rate by a factor 2 does not affect the nucleation rate of pores generated through mechanism B. However, it seems to affect the nucleation rate of small pores obtained through the mechanism A. The kinetics of growth for the majority of individual pores can be described using an exponential-like function. This kinetics is faster for mechanism B compared to mechanism A.

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In situ study on secondary dendrite arm coarsening of Sn–Bi alloy by synchrotron microradiography

Cited by 8 publications

References 10 publications

Phase field simulation of dendrite growth with boundary heat flux

Phase field simulation of dendrite growth with boundary heat flux

Local solidification thermal parameters affecting the eutectic extent in Sn-Cu and Sn-Bi solder alloys

Tracking pores during solidification of a Ni-based superalloy using 4D synchrotron microtomography

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