Title : Computer models of T-x-y Diagrams: Verification of Ag-Cu-Ni & A-Sb-Sn (A = Ag, Au, Bi, Co, Cu, In, Ni) ternary systems
Systems A-Sb-Sn (A= Ag, Au, Bi, Co, Cu, In, Ni), and more complex ones, like Ag-Cu-Ni-Au-Sn, have been elaborated to change the lead-containing solders. Ternary systems with the binary Sb-Sn will be discussed more thoroughly. A contradiction was found in these systems (e.g. Ag-Sb-Sn), which is that the incongruently melting binary compound Sb2Sn3 on some data decomposes at 242.4oC to SbSn and Sn, and on others – it exists down to 300 K. Therefore, two variants of the mono- and nonvariant states scheme were drawn up and two versions of 3D models were built and considered. The Ag-Sb-Sn T-x-y diagram, if Sb2Sn3 compound exists down to 300 K, consists of 99 surfaces, that serve as boundaries of 45 phase regions. If you consider the option, in which Sb2Sn3 decomposes at 242.4oC on SbSn and Sn, the phase diagram is built on 82 base points and consists of 103 surfaces and 49 phase regions. Ternary alloys of these systems have important applications as the lead-free solders. For the best understanding of the phase relations, firstly a 3D model of the phase diagram prototype has been assembled, visually and easily explaining graphically all the intricacies of the geometric structure of the T-x-y diagram, encoded in a table form in the scheme of mono- and nonvariant transformations. Further, after entering the real base points by which the 3D model is being built and correcting the curvature of the lines and surfaces, the prototype was transformed into a 3D model of the T-x-y diagram of the real system. The model reproduces the iso- and polythermal sections, allowing you to build any other incisions and analyze the crystallization of any original melt up to the final formation of the microstructure. These diagrams may generate the vertical (for the given center of masses) and horizontal (for the isothermal state of isopleth) material balances. This work was been performed under the program of fundamental research SB RAS (project 0336-2019-0008).