| Popis: |
Intermetallic compound Al3Ti was fabricated by reactive sintering method. Elemental powders of Al and Ti with 73, 74, 75, 76 and 77 mol%Al were pressed and heated in a hot-pressing apparatus under a vacuum of 10-2Pa. Readily dense Al3Ti was obtained under a fabrication condition of the hot-pressing temperature, 1373K, and the pressing time, 60min. Microstructures of the sintered material were dependent on the nominal Al content: Aluminum content of 76 and 77 mol%Al showed grains of about 20-40μm, while 75, 74 and 73 mol%Al had fine gains of around 2-3μm and second phase particles of about 30μm.The second phase of 73 mol%Al consists of Ti3Al and TiAl, while that of 75 mol% Al consists of TiAl. The size and number of the second phase increased with decreasing the nominal Al content. The matrix of all sintered materials was the stoichiometric Al3Ti independent of the nominal Al content. Mechanical properties were measured by Vickers hardness and compression tests. The hardness and the compression strength showed maximum around 75 mol%Al, decreased at other compositions. The relations between the microstructures and the mechanical properties were discussed. |
