Ispitivanje faznih ravnoteža i karakterizacija legura u sistemu Bi-Cu-Ni / Branislav R. Marković

Abstract

Fazne ravnoteže u Bi-Cu-Ni ternarnom sistemu proucavane su eksperimentalnim metodama (SEM-EDS, DTA i DSC), kao i analiticki primenom CALPHAD metode. Proracun ravnotežnih faznih dijagrama u Bi-Cu-Ni sistemu izveden je na osnovu optimiziranih termodinamickih parametara za sastavne binarne sisteme i dodatnih termodinamickih parametara, odredenih u ovom radu. Proracunati fazni dijagrami izotermalnih preseka na 300oC, 400oC i 500oC uporedeni su sa eksperimentalnim rezultatima iz literature i ustanovljeno je dobro medusobno slaganje. Definisani su ternarni termodinamicki parametri za tecnu fazu, i BiNi fazu u kojima je uzeta u obzir eksperimentalno potvrdena rastvorljivost bakra u BiNi fazi. Proracunati fazni dijagrami tri vertikalna preseka uporedeni su sa DTA/DSC rezultatima iz ovog rada. Odredene su tvrdoca i elektricna provodljivost kao dopunska karakterizacija legura ispitivanog Bi-Cu-Ni ternarnog sistema.

Phase equilibria in the Bi-Cu-Ni ternary system have been studied experimentally using SEM-EDS, DTA and DSC methods, and analytically using CALPHAD method. Calculation of equilibrium phase diagrams of Bi-Cu-Ni system was performed using optimized thermodynamic parameters of the constituent binary systems and additional thermodynamic parameters determined in this study. Calculated isothermal sections at 300oC, 400oC and 500oC were compared with experimental results from the literature and good agreement is found. Ternary thermodynamic parameters for the liquid phase were determined, as well as for the BiNi phase, in which the experimental confirmation of copper solubility in BiNi phase was taken into account. Three calculated vertical sections were compared with the DTA/DSC results from this work. Hardness and electrical conductivity as an additional characterization of the investigated alloys of Bi-Cu-Ni ternary system were determined.