Experimental investigation and thermodynamic calculation of the B-Fe-W ternary system

The ternary B-Fe-W system is of interest for the wear resistant applications. Its liquidus projection in the Fe-rich region was experimentally determined and thermodynamic modeling was performed in this work. The microstructures of the solidified samples were observed by scanning electron microscopy, the compositions of the primary crystallization phases were obtained by electron probe microanalysis, and the reaction temperatures were determined by differential scanning calorimetry. The observed primary solidification phases are BCC (Fe), FCC, WFeB, Fe2B, μ, and BCC (W), respectively. A thermodynamic model of the B-Fe-W system based on thermodynamic models of the three constituent binary systems and the experimental results for the ternary system was developed using the CALPHAD approach. A set of self-consistent thermodynamic parameters for the B-Fe-W system was obtained and reasonable agreement between the experimental and calculated isothermal sections and liquidus projection was obtained.