Evaluation of Phase Equilibria Involving the Liquid Phase in the Hf-Si System

Author(s)

Gigolotti, J. C. J. ^[1] ; Nunes, C. A. ^[2] ; Suzuki, P. A. ^[2] ; Coelho, G. C. ^[2]

Affiliation

^[1] Nucleo Pesquisa UniFOA, Ctr Univ Volta Redonda, BR-27240560 Rio De Janeiro - Brazil

^[2] Univ Sao Paulo, EEL, Dept Engn Mat DEMAR, BR-12600000 Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION; v. 35, n. 5, p. 622-630, OCT 2014.
• Web of Science Citations: 1

Abstract

Metal-silicon-boron (Me-Si-B) alloys have been extensively studied due to their potential to develop high temperature structural materials. In this sense, information from accurate phase diagram becomes important. This work presents results of detailed microstructural characterization of as-cast hafnium-silicon alloys to assess the liquid composition associated to the invariant reactions of this system. The alloys were prepared by arc melting from high purity hafnium and silicon under argon atmosphere. The phases present in the alloys were identified by scanning electron microscopy and x-ray diffraction. Important discrepancies were found between the data obtained in this work and those of the most recent phase diagrams, especially the composition of the liquid phase in the following reactions: L + Hf5Si3 reversible arrow Hf2Si, 32.5 at.% Si instead of 21 at.% Si, L + Hf3Si2 reversible arrow Hf5Si3, 37.0 at.% Si instead of 30.3 at.% Si and L + Hf5Si4 reversible arrow HfSi, 52.5 at.% Si instead of 58.3 at.% Si. (AU)

• FAPESP's process: 07/05206-5 - Experimental study of the Hf-Si-B system
• Grantee: Carlos Angelo Nunes
• Support Opportunities: Regular Research Grants