Effect of zirconium addition on the phase transformations in as-cast and heat-treated Ti-Zr-Si-B alloys

This work reports on effect of zirconium addition on the phase transformations in as-cast and heat-treated Ti-6.7Zr-22.2Si-11.1B, Ti-7Zr-15Si-7.5B, Ti-7Zr-10Si-5B, Ti-7Zr-7.5Si-15B and Ti-7Zr-30Si-5B alloys (at.%). After arc melting, these Ti-Zr-Si-B alloys were heat-treated at 1200 °C for 90 h. Samples of as-cast and heat-treated Ti-Zr-Si-B alloys were evaluated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and wavelength X-ray dispersive spectrometry. Nanosized eutectic structure constituents were observed in microstructures of as-cast Ti-Zr-Si-B alloys. TiSS (ss-solid solution), Ti6Si2B, TiB and Ti5Si3 dissolved up to 5.3, 14.2, 1.5 and 11.6 at.% Zr, respectively, which is in agreement with the shift of their peaks toward smaller diffraction angles.