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Atomic Ordering Behavior of CoTi Alloy with Addition of Transition Metals

Hussain Abid, Ziya Amer Bashir, Atiq Shabbar, Saleem Muhammad, Ullah Mahtab, Ahmad Sajjad, Ahmad Naseeb

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 2

425--430

EN

The statistical-thermodynamic theory of ordering and electronic theory of ordering in the pseudo-potential approximation was used to study the influence of ternary addition of some transition metals on the atomic ordering behavior of Co0.5(Ti1-xMx)0.5 alloys with M = Fe, Pt, re, V, Cr, Mn, Ni, Cu, Zn, Zr, Ag, Hf or Au up to a concentration of 1 at.%. The partial ordering energies, order-disorder phase transformation temperatures and partial short range order parameters have been calculated for these alloys. The analysis shows that the impurity elements in Co0.5(Ti1-xMx)0.5 alloys can be divided into two main groups on the basis of lattice site occupancy i.e. M = V, Cr, Mn, Cu, Zn, Zr, Ag, Hf and Au mainly substitute for Co sublattice sites whereas M = Fe, Ni, Pt or re mainly substitute for Ti sublattice sites. Further, the order-disorder transformation temperatures were found to either increase or remain nearly unchanged by the addition of ternary impurities in the CoTi alloy depending on the absolute value of the partial ordering energies. Alloys of Ti with V, Cr, mn, Cu, Zn, Zr, Ag, Hf or Au in place of Co and alloys of Co with Fe, Ni, Pt or Re in place of Ti can be predicted for future. The results of the present analysis are in good agreement with the available experimental data on these alloys.

2

Ab-initio study of structural, elastic, electronic and thermodynamic properties of BaxSr1-xS ternary alloys

Chelli S., Touam S., Hamioud L., Meradji H., Ghemid S., Hassan F. E.

Materials Science Poland

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2015

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Vol. 33, No. 4

879--886

EN

The structural, elastic, electronic and thermodynamic properties of BaxSr1-xS ternary alloys have been investigated using the full-potential (linearized) augmented plane wave method. The ground state properties, such as lattice constant, bulk modulus and elastic constants, are in good agreement with numerous experimental and theoretical data. The dependence of the lattice parameters, bulk modulus and band gap on the composition x was analyzed. Deviation of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence (LCD) was observed. The microscopic origins of the gap bowing were explained by using the approach of Zunger et al. The thermodynamic stability of BaxSr1-xS alloy was investigated by calculating the excess enthalpy of mixing, Delta H-m and the calculated phase diagram showed a broad miscibility gap with a critical temperature.

3

Numerical approach to predicting thermodynamic properties of ternary alloys

Romanowska J.

Inżynieria Materiałowa

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2011

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Vol. 32, nr 6

929-932

EN

This paper presents a new numerical approach to the modelling of ternary systems on the basis of the thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting exGfi ijk values is regarded as the calculation of the values of an exGfi function inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of exGfi on all arms of the triangle are known (exGfi ij, exGfi ik, exGfi jk). This approach is contrary to finding a function value outside a certain area, if the function value inside this area is known. exGfi ijk and Lfi ijk ternary interaction parameters in the Muggianu extension of Redlich-Kister formalism are calculated numerically by use of the Excel program and Solver. The results of the calculations were compared to the data for the Cu-Sn-Zn and Bi-Cu-Ni systems obtained by means of the CALPHAD method.

PL

W pracy przedstawiono numeryczną metodę prognozowania właściwości termodynamicznych stopów trójskładnikowych na podstawie danych termodynamicznych stopów dwuskładnikowych, tworzących badany stop trójskładnikowy. Wartości exGfi ijk wyznaczono jako wartości funkcji exGfi wewnątrz obszaru (trójkąta składów Gibbsa), gdy są znane wszystkie wartości brzegowe, czyli wartości exGfi na bokach trójkąta (exGfi ij, exGfi ik, exGfi jk). Prezentowane podejście jest odwrotne do szukania wartości funkcji na zewnątrz obszaru dla znanych wartości funkcji wewnątrz danego obszaru. Wartości funkcji exGfi ijk i parametrów Lfi ijk równania Redlicha-Kistera wyznaczono numerycznie, korzystając z programu Excel i dodatku Solver. Wyniki obliczeń dla stopow Cu-Sn-Zn i Bi-Cu-Ni porównano z danymi uzyskanymi metodą CALPHAD.

4

Segregacja srebra podczas krystalizacji kierunkowej stopu Al-Ag-Cu

Konopka Z., Nocuń S., Zyska A., Bober A., Cisowska-Łągiewka M.

Archiwum Odlewnictwa

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2005

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R. 5, nr 15

216--221

PL

W pracy przedstawiono segregację srebra występującą podczas krystalizacji kierunkowej potrójnego stopu Al-Ag-Cu, oraz jej wpływ na stabilność frontu krystalizacji podczas krystalizacji kierunkowej. Badania wykazały silną segregację Ag zarówno w fazie α(Al) w stopie, jak i w cieczy przed frontem krystalizacji. Segregacja ta nie wpływa bezpośrednio na parametry struktury, jednakże zauważony został dość silny jej wpływ na stabilność frontu krystalizacji.

EN

In this paper it was shown the segregation of the ternary element Ag which oc-curs during unidirectional solidification of the ternary Al-Ag-Cu system, as well as its influence on the stability of solid-liquid interface. The result confirmed strong segregation of the silver not only in the liquid on the solid-liquid interface but also in the α(Al) phase. This segregation doesn’t have visible influence on the structures parameters but it has been observed the influence of this segregation on the solid-liquid interface.