A unified approach to phase and microstructural stability for Fe-ETM alloys through Miedema's model

Ghosh, Sadhan; Basu, Joysurya; Divakar, R.; Mohandas, E.; Vijayalakshmi, M.

doi:10.1016/j.intermet.2011.11.016

Cited by 22 publications

(10 citation statements)

References 55 publications

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“…It has been observed experimentally and theoretically that Laves phase forming compositions are better glass formers [15]. Moreover, bulk metallic glasses 2 C. Ghosh et al…”

Section: Introductionmentioning

confidence: 97%

“…Although the physics of dispersion strengthening is relatively better understood, degradation of mechanical properties due to uncontrolled precipitation of Laves phases in structural materials and steels is almost not understood [14]. It has been postulated that the precipitation of Laves phases in steel matrix reduces solid solution strengthening effects and additionally contributing factors like inherent limited plasticity of the phase and the weak precipitate-matrix interface lead to such degradation [15]. It definitely warrants further studies to understand the structure and chemistry of such phases and interfaces in order to mitigate such problems.…”

Section: Introductionmentioning

confidence: 99%

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Structure imaging and vanadium substitution in cubic TiCr₂Laves phase

Ghosh

Sharma

Basu

et al. 2015

Philosophical Magazine

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Properties of Laves phase compounds can be tailored by alloying and microstructural engineering. V-substituted cubic TiCr 2 Laves phase has been studied to understand the location of V atoms in the lattice, by structural imaging and first-principle computations. Even though Ti, V and Cr appear next to each other in the periodic table, V preferentially replaces the Ti lattice producing anti-site defects. The defect formation energy for V substitution in Ti and in Cr lattice is 0.29 and 0.40 eV, respectively. V replacement in the Ti lattice generates atomic scale strain. Atomic numbers of V, Ti and Cr being very close, this phase is not quite suitable for incoherent imaging for understanding the structure and the chemistry. Instead, difference in channelling behaviour of electron waves along the Ti columns and along the Cr columns could be exploited to preferentially image the individual atom columns. Nature of the exit phase wave, phase and amplitude has been used to understand the contrast qualitatively. The intensity distribution of any particular atom column that is disturbed by the presence of foreign atom has been used to detect the position of V atoms. This method could be extended to study other Laves phases and complex intermetallic structures to understand their structure, defects and interfaces. IntroductionLaves phases, a group of topologically close-pack hard intermetallic compounds with AB 2 stoichiometry, are known to form at a particular radius ratio of A and B (r A /r B = 1.22) atoms [1]. However, a considerable deviation from ideal radius ratio (r A /r B = 1.05-1.67) [2] is observed in practice and the phase can often accommodate non-stoichiometry [3]. There are three allotropic polymorphs of Laves phase i.e. cubic (cF24), hexagonal (hP12) and double-hexagonal (hP24) [2]. Since the discovery of this phase, more than a thousand binary and ternary Laves phase forming compounds with a range of interesting properties and varying crystal chemistry have been reported in the literature [4]. These attributes could be exploited to design single-phase or multiphase

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“…It has been observed experimentally and theoretically that Laves phase forming compositions are better glass formers [15]. Moreover, bulk metallic glasses 2 C. Ghosh et al…”

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Structure imaging and vanadium substitution in cubic TiCr₂Laves phase

Ghosh

Sharma

Basu

et al. 2015

Philosophical Magazine

Self Cite

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“…It is thereby interpreted that Laves phase is a rather stable precipitate in this temperature regime, and not metastable as has been misconceived in the past [12]. It needs to be emphasized that as the ageing process continues, the material under consideration hops from one energy minima to another energy minima leading to a change in the microstructure [4]. Another intriguing observation, which the reader can draw from these isothermal sections, is the chemical composition of Laves phase.…”

Section: Thermodynamic Modellingmentioning

confidence: 97%

“…to PAGBs [2]. Amongst these however, the major consensus view point has been the nucleation and growth of complex hard and brittle Laves phases (topologically close packed intermetallic compounds with AB 2 stoichiometry) [4,5], on grain and lath boundaries [6].…”

Section: Introductionmentioning

confidence: 99%

Understanding Laves phase precipitation induced embrittlement of modified 9Cr–1Mo steel

Sarwat

Basu

2018

SN Appl. Sci.

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Precipitation of Laves phase in steels is often identified as the primary cause for the degradation of mechanical properties. Analytical electron microscopy and thermodynamic modelling have been used in this study to understand the Lave phase precipitation induced damage initiation process in modified 9Cr-1Mo steel, exposed to high temperature for 10,000 h. The results have suggested that in addition to void nucleation at the interface and de-cohesion, the limited plasticity of the Laves phase is also a predominant mechanism for crack initiation in this material. The thermodynamic propensity of Laves phase precipitation around the carbides and the underlying role of local chemistry have also been studied. Binary Laves phases have been found to be stabilized by ternary additions.

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“…In situations where a large number of alloys have to be considered in the absence of a prior thermodynamic database, the Miedema model provides an excellent starting point. This model has been extensively used by Murty et al [1], Basu et al [8], and In any system, binary or higher order, the elastic enthalpy and chemical enthalpy of mixing plays an imperative role in affecting the phase stability. Egami [10] proved that increasing the number of elements involved, increasing the atomic size ratio, increasing the attractive force between small and large atoms, and introducing a repulsive potential between small atoms will help the formation of bulk metallic glasses.…”

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confidence: 99%

A new thermodynamic parameter GCE for identification of glass forming compositions

Sarwat

Ramya

Ali³

et al. 2015

Journal of Alloys and Compounds

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A unified approach to phase and microstructural stability for Fe-ETM alloys through Miedema's model

Cited by 22 publications

References 55 publications

Structure imaging and vanadium substitution in cubic TiCr₂Laves phase

Structure imaging and vanadium substitution in cubic TiCr₂Laves phase

Understanding Laves phase precipitation induced embrittlement of modified 9Cr–1Mo steel

A new thermodynamic parameter GCE for identification of glass forming compositions

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A unified approach to phase and microstructural stability for Fe-ETM alloys through Miedema's model

Cited by 22 publications

References 55 publications

Structure imaging and vanadium substitution in cubic TiCr2Laves phase

Structure imaging and vanadium substitution in cubic TiCr2Laves phase

Understanding Laves phase precipitation induced embrittlement of modified 9Cr–1Mo steel

A new thermodynamic parameter GCE for identification of glass forming compositions

Contact Info

Product

Resources

About

Structure imaging and vanadium substitution in cubic TiCr₂Laves phase

Structure imaging and vanadium substitution in cubic TiCr₂Laves phase