Phase equilibria in the Cr-Si-Ti system below 40 at.% Si

• Published in: Journal of alloys and compounds Vol. 785; pp. 897 - 910
• Main Authors: Bulanova, M., Tedenac, J.C., Fartushna, I., Meleshevich, K., Darmostuk, K.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-05-2019; Elsevier BV; Elsevier
• Subjects: Chemical Sciences; Chromium; Cr-Si-Ti system; Crystal structures; Crystallization; Differential thermal analysis; Electron probe microanalysis; Electron probes; Liquidus; Melts; Nomograms; Phase equilibria; Phase transformations; Phase transitions; Scanning electron microscopy; Silicon; Solid solutions; Solidus; Ternary systems; X-ray diffraction; Phase equilibria; Crystal structures; Cr-Si-Ti system; Phase transformations
• DOI: 10.1016/j.jallcom.2019.01.222
• EISSN: 1873-4669
• ISSN: 0925-8388

Phase transformations in the Cr-Si-Ti ternary system have been studied using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) at silicon content <40 at.%. Partial liquidus and solidus projections and the melting diagram (solidus + liquidus) have been constructed. Some sections as partial isothermal at 1450 and 1150 °C, isopleths at 10 at.% Si and 50 at.% Ti are described. The liquidus surface is characterized by the presence of primary crystallization regions of a solid solution (Cr,βTi) and binary based phases (Cr3Si), (Ti5Si5) and the Laves-phase C14, which is stabilized by additions of silicon, and in the ternary system melts congruently above 1600 °C. The solidus surface is characterized by the presence of three-phase fields: (γTiCr2) + (Cr3Si) + (Cr,βTi), (Ti5Si3) + (γTiCr2) + (βTi,Cr) and (Ti5Si3) + (γTiCr2) + (Cr3Si). The former two regions form invariant four-phase eutectic equilibria L ↔ (βTiCr2) + (Cr3Si) + (Cr,βTi) and L ↔ (Ti5Si3) + (γTiCr2) + (βTi,Cr) at 1534 and 1243 °C, respectively. The maximum of the solidus temperature of about 1580 °C is observed in the field (γTiCr2) + (Cr,βTi). At 1495 °C the solid-state transformation (γTiCr2) + (Cr3Si) ↔ (Ti5Si3) + (Cr,βTi) takes place.
•Phase relations in Cr-Si-Ti system have been studied experimentally.•Partial liquidus and solidus projections have been constructed.•Partial isothermal sections at 1450, 1150 °C, isopleths at 10 at.% Si, 50 at.% Ti were constructed.•γTiCr2 is stabilized by additions of Si, and in the ternary system melts congruently at >1600 °C.