Ab initio comparative study of the Cu-In and Cu-Sn intermetallic phases in Cu-In-Sn alloys

S. RAMOS DE DEBIAGGI; C. DELUQUE TORO; G. F. CABEZA; A. FERNÁNDEZ GUILLERMET

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2012 vol. 542 p. 280 - 292

0925-8388

The present paperreports a comparative account of the structural, cohesive and thermodynamicstability properties of the binary intermetallic phases (IPs) occurring in theCu-In and the Cu-Sn phase diagrams, both at low and at high temperatures, basedupon systematic density-functional-theory (DFT) calculations. Using theprojector augmented wave method and the exchangeand correlation functions of Perdew and Wang in the generalized gradientapproximation (GGA), as well as the local-density-approximation (LDA) with theCeperley and Alder exchange and correlation potentials, we determine thelattice-parameters, molar volume, bulk modulus and its pressure derivative, theelectronic density of states (DOS) and the energy of formation (EOF) from theelements of the d-Cu7In3(aP40), g-Cu9In4(cP52) and CuIn2 (tI12) compounds of the Cu-In system. Moreover, DFT-GGAcalculations were performed for the compounds: g-Cu4Sn(cF16), x-Cu10Sn3(hP26), e-Cu3Snboth in the (oP8) structure and the (oP80) superstructure, h´-Cu6Sn5 (mC44) and h-Cu5Sn4 both in the h1 (mP36) and h2 (mC54) structural forms. In addition, thehypothetical structures obtained by replacing In (or Sn) by Sn (or In) arestudied, because of their relevance in the CALPHAD modeling of the Cu-In-Snphase diagram. The work includes a discussionof the composition dependence of the structural and equation-of-state parameters,the electronic DOS, the EOF of the compounds and the differences between theresults of the GGA or LDA calculations and the measured values. Besides,various quantities expressing the relative stability of the IPs are introducedand compared with experimental data and with indirect information obtained in aCALPHAD-type two-sublattice modeling of the Cu-In-Sn  phase diagram.