Isothermal Section of the V-Si-B System at 1600 °C in the V-VSi2-VB Region (original) (raw)

2009, Journal of Phase Equilibria and Diffusion

In recent years, the Me-Si-B (Me-metal) ternary systems have received considerable attention aiming at the development of high-temperature structural materials. Assuming that any real application of these materials will rely on multicomponent alloys, as is the case of Ni-base superalloys, phase equilibria data of these systems become very important. In this work, results are reported on phase equilibria in the V-Si-B system, and are summarized in the form of an isothermal section at 1600°C for the V-VSi 2-VB region. Several alloys of different compositions were prepared via arc melting and then heat-treated at 1600°C under high vacuum. All the materials in both as-cast and heat-treated conditions were characterized through x-ray diffraction, scanning electron microscopy, and selected alloys via wavelength dispersive spectroscopy. A negligible solubility of B in the V 3 Si, V 5 Si 3 (T 1), and V 6 Si 5 phases as well as of Si in V 3 B 2 and VB phases was noted. Two ternary phases presenting the structures known as T 2 (Cr 5 B 3prototype) and D8 8 (Mn 5 Si 3-prototype) were observed in both as-cast and heat-treated samples.