The melting diagram of the Ti-corner of the Ti–Zr–Si system and mechanical properties of as-cast compositions

• Published in: Journal of alloys and compounds 2004-12, Vol.384 (1-2), p.106-114
• Main Authors: Bulanova, M., Firstov, S., Gornaya, I., Miracle, D.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Melting diagram; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Ti-corner; Ti–Zr–Si system; Tribology and hardness
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2004.02.060

Phase equilibria in the Ti-corner of the Ti–Zr–Si system were studied by the methods of metallography, differential thermal analysis, X-ray and microprobe analyses of as-cast samples. The results are given in the way of the melting diagram and of polythermal sections at 10 and 20at.% Si. At 1300°C invariant four-phase equilibrium of eutectic type L↔〈β-Ti〉(β)+〈Ti5Si3〉(Z)+〈(Ti,Zr)2Si〉 (S2) was shown to occur in the concentration interval studied. The location of the eutectic point E was determined to take place at ∼78Ti–11Zr–11Si. The ternary compound S2 formed from the melt by peritectic reaction L+Z→S2. Microhardness of the primary silicide grains and of eutectics microconstituents has shown that zirconium additions decrease the strength of the Z-phase and of the β+Z eutectic, while they do not change the strength of the S2-silicide and of the β+S2 eutectic. Based on the results of hot hardness measurements, below 550°C the potential for attractive high-temperature structural properties is controlled by refinement of the microstructure, while above this temperature the α↔β transformation temperature of Ti limits the application.