Influence of Sintering Conditions on Compacted Rapidly Solidified AlFeCrSiTi Alloys

A. Knaislová, A. Michalcová, I. Marek, Z. Veselka, J. Vavřík Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Prague, Technická 5, 166 28 Praha 6, Czech Republic

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This work is devoted to the preparation of AlFeCrSiTi alloys by powder metallurgy using melt atomization and spark plasma sintering. Conventional aluminium alloys are characterized by low density but their main problem is thermal stability. The strengthening fine precipitates coarsen at temperature above 300° in few minutes, which leads to decrease of mechanical properties. As a solution for this problem, it is suggested to prepare Al-TM (transition metal) alloys by rapid solidification, which leads to presence of big amount of fine Al-TM intermetallics slowing down diffusion and suppressing recrystallization because the Al-TM precipitates are predominantly located at the grain boundaries and triple junction of grains. The rapid solidification process also causes formation of metastable phases, e.g. supersaturated solid solution and quasicrystals. Decomposition of both these phases brings feasibility of self-healing properties to the alloy. Self-healing behaviour of alloy means the ability to close and heal micro- or nanoscaled crack present in material. In case of rapidly solidified alloys, the expected mechanisms are precipitation from supersaturated solid solution or decomposition of quasicrystals accompanied by change of size and shape of intermetallic particles. Microstructure and selected mechanical properties of bulk AlFeCrSiTi alloy were studied by transmission electron microscopy, X-ray diffraction, and compressive testing.

DOI:10.12693/APhysPolA.134.738 PACS numbers: 61.66.Dk, 61.05.cp, 62.20.mt