Influence of hot pressing temperature on microstructure and selected properties of composite sinters with iron aluminides
Anita Olszówka-Myalska*, Katarzyna Konopka*, Roman Przeliorz** *Politechnika Śląska, Wydział Inżynierii Materiałowej i Metalurgii, ul. Krasińskiego 8b, 40-019 Katowice **Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa
Annals 4 No. 12, 2004 pages 359-362
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abstract The composite sinters obtained from aluminium powder (Fig. 1a) and iron powder (Fig. 1b) mixture as a result of hot pressing in vacuum in Degussa press at a temperature range 560÷630oC were investigated. All sintered materials were obtained from the powders mixture of composition of Al 90 vol.% and Fe 10 vol.%. The pressure 15 MPa and sintering time 30 min were used. The results of differential thermal analyse (DTA) of a mixture of aluminium powder and iron powder showed interaction between components (Fig. 2) below aluminium melting point. Microstructure observation of a composite samples by SEM Hitachi-4200S showed in aluminium matrix the presence of iron aluminides particles formed as a result of interaction between iron powder and matrix (Figs. 3-6). Differences of particles microstructure were noticed. In materials hot pressed at a temperature range 560÷600oC, the intermetallic particles were globular, with shape similar to the precursor iron powder, and they increased with a temperature increase. In materials hot pressed at a temperature of 620 and 630oC a new phase was disspersed. The experiment showed the possibility of in situ formation of iron aluminide with a different morphology in aluminium matrix composite. The increase of density, hardness, Young modulus E and Kirchhoff G modulus with hot pressing temperature was stated (Table 1). Key words: in situ composites, aluminides, hot pressing