Reaction layers around SiC particles in Ti: an electron microscopy study

• Published in: Acta materialia 1999-08, Vol.47 (10), p.3105-3116
• Main Authors: Kooi, B.J., Kabel, M., Kloosterman, A.B., De Hosson, J.Th.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbides; Dispersion hardening metals; Exact sciences and technology; Laser treatment; Metals. Metallurgy; Microstructure; Powder metallurgy. Composite materials; Production techniques; Titanium; Transmission electron microscopy (TEM)
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(99)00151-2

A detailed description is given of the microstructure of the top layer of Ti–6Al–4V with SiC particles embedded with a high-power Nd:Yag laser system. Scanning electron microscopy (SEM), as well as conventional, analytical and high-resolution transmission electron microscopy (TEM) were used. An existing controversy about the presence or absence of Ti 3SiC 2 in the reactive SiC/Ti systems is clarified and the first observations of Ti 5Si 3 precipitation on stacking faults in Si supersaturated TiC are reported. The Si released during the reaction SiC+Ti→TiC+Si results in the formation of Ti 5Si 3. If in the reaction layer regions in between the TiC grains become enclosed, the rejected Si content increases locally and Ti 3SiC 2 plates with dominant (0001) facets nucleate. In the TiC grains particularly of the cellular reaction layer, a high density of widely extending stacking faults of the order of 100 nm is observed and on these faults in many instances small Ti 5Si 3 precipitates are present.