Microstructure and mechanical properties of cast in-situ TiAl matrix composites reinforced with (Ti,Nb)2AlC particles
| Autor: | Zuzana Gabalcová, A. Klimová, Oto Bajana, Juraj Lapin, T. Pelachová, Michaela Štamborská |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Mechanical Engineering Charpy impact test 02 engineering and technology 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Grain size Carbide Fracture toughness Mechanics of Materials 0103 physical sciences Vickers hardness test Volume fraction lcsh:TA401-492 lcsh:Materials of engineering and construction. Mechanics of materials General Materials Science Lamellar structure Composite material 0210 nano-technology |
| Zdroj: | Materials & Design, Vol 133, Iss, Pp 404-415 (2017) |
| ISSN: | 0264-1275 |
| DOI: | 10.1016/j.matdes.2017.08.012 |
| Popis: | The in-situ TiAl matrix composites with nominal compositions of Ti-44.5Al-8Nb-0.8Mo-0.1B-xC (at.%), where x is ranging from 1.4 to 4.8 at.%, were prepared by casting. The microstructure of the as-cast composites consists of primary (Ti,Nb)2AlC particles distributed in the matrix composed of lamellar γ(TiAl) + α2(Ti3Al) and γ phase regions with a small amount of β/B2 phase. The chemical composition of some coarse carbides is not homogeneous and central regions enriched by C are identified to be (Ti,Nb)C phase. The mean aspect ratio of the primary carbide particles decreases and their volume fraction and shape factor increase with increasing content of C. A linear relationship is identified between the volume fraction of the carbide particles and average content of C in the composites. The heat treatments lead to the formation of fine secondary carbide particles within the matrix. The mean grain size of the as-cast composites increases during the heat treatments. The Vickers hardness, compression yield strength, Charpy impact value and dynamic fracture toughness of the heat-treated composites decrease with the increasing volume fraction of carbide particles. The brittle fracture behaviour of the in-situ composites includes crack deflection, delamination on the matrix-carbide interfaces and pull-out of the carbide particles from the γ matrix. Keywords: Titanium aluminides, TiAl, Composites, Microstructure, Mechanical properties |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect