Phase equilibria, thermodynamics and solidification microstructures of Mg–Sn–Ca alloys, Part 1: Experimental investigation and thermodynamic modeling of the ternary Mg–Sn–Ca system

Kozlov, Artem; Ohno, Munekazu; Arróyave, Raymundo; Liu, Zhe; Schmid–Fetzer, Rainer

doi:10.1016/j.intermet.2007.10.010

Cited by 90 publications

(49 citation statements)

References 28 publications

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“…The microstructure contains grains of up to 500 µm in size and consists of two phase structures, namely Mg 2 Ca (present mainly along the grain boundaries) and the CaMgSn (needle like ternary phase observed mostly within the matrix which is a solid solution of Mg and Sn [9]). This confirms the predictions of Kozlov et al [24] from thermodynamic modelling of Mg-SnCa ternary phase diagram that when the Sn/Ca ratio is 1.5, as in TX32, CaMgSn and Mg 2 Ca phases form during solidification [25]. Because of their high melting points, these intermetallic particles are thermally stable and are effective in improving the creep resistance of TX series alloys.…”

Section: Cast and Homogenized (Ch) Alloy Microstructuresupporting

confidence: 88%

Comparative study of microstructure and texture of cast and homogenized TX32 magnesium alloy after hot deformation

Dharmendra

Rao

Prasad³

et al. 2015

Met. Mater. Int.

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The effect of homogenization on the hot deformation behavior and texture evolution of Mg-3Sn-2Ca (TX32) alloy is investigated. The cast-homogenized alloy samples were hot compressed in the temperature and strain rate ranges of 300-500°C and 0.0003-10 s -1 , respectively, and a processing map has been developed by using the flow stress data. The map revealed two dynamic recrystallization (DRX) domains with a peak efficiency of 44% at 360°C/0.0003 s -1 (Domain 1) and 43% at 485 ○ C/0.1 s -1 (Domain 2). When compared with the map for as-cast condition, it is observed that both the domains moved towards higher temperatures although the shift of Domain 1 is more noticeable. The apparent activation energy values in the two domains and the regime of flow instability are nearly unchanged by homogenization, suggesting that Mg2Ca and CaMgSn particles in the microstructure are thermally stable. Specimens deformed under conditions in Domain 1 have high Schmid factors for {0001} <1120> basal slip and {1100} < 1120> prismatic slip, while in Domain 2 the deformation progressed due to {112 2} <112 3> second-order pyramidal slip.

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Section: Cast and Homogenized (Ch) Alloy Microstructuresupporting

confidence: 88%

Comparative study of microstructure and texture of cast and homogenized TX32 magnesium alloy after hot deformation

Dharmendra

Rao

Prasad³

et al. 2015

Met. Mater. Int.

View full text Add to dashboard Cite

show abstract

“…3(b)) where Mg 2 Sn phase perfectly dissolves into the matrix. According to the thermodynamic data, 12) The Effect of Microstructure Evolution on the Elevated Temperature Mechanical Properties in Mg-Sn-Ca Systemcomposition. To predict the microstructure evolution more clearly, the solidification behavior was calculated by Scheil's model 15,16) (complete mixing in liquid, no diffusion in solid).…”

Section: Methodsmentioning

confidence: 99%

“…10,11) More recently, A. Kozlov et al have studied on the phase equilibria of Mg-Sn-Ca system using CALPHAD method. 12,13) However, close examination on the role of respective 2nd phases on high temperature mechanical properties has not been performed in detail. Therefore, in this study, the effect of microstructural evolution on the high temperature properties in Mg-Sn-Ca system has been investigated.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Microstructure Evolution on the Elevated Temperature Mechanical Properties in Mg-Sn-Ca System

et al. 2008

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The effect of microstructural evolution on the creep properties in Mg-Sn-Ca system has been investigated. As-cast microstructure of MgSn-Ca alloy consists of two or three phases depending on the Ca/Sn ratio, i.e. Mg 2 Sn, CaMgSn and Mg 2 Ca phases. Ternary CaMgSn phase has two types of morphology by its pseudo hyper-eutectic reaction with -Mg; coarse rod-like primary or feather-like eutectic phase. Primary solidified CaMgSn phase exhibit negative effect on the tensile properties in spite of its high thermal stability up to 500 C. According to the creep test results, apparent stress exponent value (n ¼ 7) indicates climb controlled creep mechanism by core diffusion above 150 C. Activation energy of Mg-5Sn-2Ca alloy (74 kJ/mol) is close to grain boundary diffusion for pure magnesium, 92 kJ/mol. Creep resistance is remarkably improved with the presence of Mg 2 Ca phase.

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“…The decision made for the enthalpy of formation of Ca 2 Sn is also of the utmost importance for calculations in multicomponent Ca-Sn-Mg alloy systems, such as the extension of the Ca 2 Sn liquidus surface and other equilibria involving this dominating phase. [121] In the ternary Al-Ni-Y system, ten ternary compounds were investigated [118] using the quasi-harmonic approximation to obtain both enthalpy and entropy of formation. They are used in the prediction of the Al-rich region of the Al-CoNi-Y system, resulting in good agreement between phase fractions from the Scheil simulation when compared with experimentally determined data for three Al-rich quaternary alloys.…”

Section: Thermodynamics At Finite Temperaturesmentioning

confidence: 99%

First-Principles Calculations and CALPHAD Modeling of Thermodynamics

Liu

2009

J. Phase Equilib. Diffus.

340

112

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Thermodynamics is the key component of materials science and engineering. The manifestation of thermodynamics is typically represented by phase diagrams, traditionally for binary and ternary systems. Consequently, the applications of thermodynamics have been rather limited in multicomponent engineering materials. Computational thermodynamics, based on the CALPHAD approach developed in the last few decades, has released the power of thermodynamics and enabled scientists and engineers to make phase stability calculations routinely for technologically important engineering materials. Within the similar time frame, first-principles quantum mechanics technique based on density functional theory has progressed significantly and demonstrated in many cases the accuracy of predicted thermodynamic properties comparable with experimental uncertainties. In this paper, the basics of the CALPHAD modeling and first-principles calculations are presented emphasizing current multiscale and multicomponent capability. Our research results on integrating first-principles calculations and the CALPHAD modeling are discussed with examples on enthalpy of formation at 0 K, thermodynamics at finite temperatures, enthalpy of mixing in binary and ternary substitutional solutions, defect structure and lattice preference, and structure of liquid, super-cooled liquid, and glass.

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Phase equilibria, thermodynamics and solidification microstructures of Mg–Sn–Ca alloys, Part 1: Experimental investigation and thermodynamic modeling of the ternary Mg–Sn–Ca system

Cited by 90 publications

References 28 publications

Comparative study of microstructure and texture of cast and homogenized TX32 magnesium alloy after hot deformation

Comparative study of microstructure and texture of cast and homogenized TX32 magnesium alloy after hot deformation

The Effect of Microstructure Evolution on the Elevated Temperature Mechanical Properties in Mg-Sn-Ca System

First-Principles Calculations and CALPHAD Modeling of Thermodynamics

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