[P35] Phase equilibrium of the B-Cr-Nb system at the Cr-Nb side

Equilibrium conditions of the invariant type and phase diagrams are explained considering the phase rule (degrees of freedom) and solubility limits. The Tammann method to determine eutectic composition and solubility limits by experimental procedure is exemplified. Also, the eutectic binary reaction and morphology of different alloys, including the eutectic structure are presented, using as example, combinations of various common metals, including Al-Si alloys and ferrous castings. The modification of phase diagrams of this type due to the addition of elements such as Na in Al-Si or S in Fe-C is described and also shown using micrographs. The peritectic, monotectic, and sintectic binary reactions are detailed as well (phase diagrams, cooling curves, and microstructures). Basic concepts and examples of computational calculation methods (CALPHAD) are also described.