Ceramics International 43 (2017) 7290–7294
Microstructure and microindentation of Ti3SiC2–Titanium filler brazed joints by tungsten inert gas (TIG) process.
Y. Hadji (1) , A. Tricoteaux (2) , M.G. Ben Ghorbal (2) , M. Yahi (3) , R. Badji (3) , T. Sahraoui (1, 3) , M.
Hadji (1, 3) ,M.W. Barsoum (1).
(1) Laboratoire des Aeronefs, University of Blida 1, Route de Soumaa, Blida 9000, Algeria (2) Laboratoire LMCPA, Université de Valenciennes, France
(3) Centre de Recherche Technologie Industriel, CRTI, Cheraga, Alger, Algeria
(4) Department of Materials Science and Engineering, Drexel University, Philadelphia, USA
Abstract
Herein we study the joining of Ti3SiC2- a MAX phase - with a Ti filler (Ti3SiC2/Ti-filler) using a TIG-brazing process. The microstructures of the interfaces were investigated by scanning electron microscopy and energy dispersive spectrometry. When Ti3SiC2 comes into contact with the molten Ti -filler during the TIG-brazing operation, it starts decomposing into TiCx and a Si-rich liquid. Simultaneously, the molten Ti infiltrates into the Ti3SiC2 resulting in a 200 µm thick duplex region, comprised of TiCx and a Ti-rich phase with some dissolved Si. Both Si and C are found in the solidified Ti; the Si source is from the Si-rich liquid, while the presence of C indicates that some of the C diffused into the Ti. Upon cooling, C- containing Ti-rich lamellae form the solidified Ti. Micro-indentation results of the decomposed Ti3SiC2 layer show an increase in hardness and a decrease in elastic modulus relative to T3SiC2. Notably, no cracks were observed.
Key words: MAX Phases, Microstructures, Joining, Hardness, Micro-indentation.
