Influence of Sintering Temperature on the Structure and Properties of Powder Iron Aluminide Fe 3 Al
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SINTERED METALS AND ALLOYS INFLUENCE OF SINTERING TEMPERATURE ON THE STRUCTURE AND PROPERTIES OF POWDER IRON ALUMINIDE Fe3Al O.I. Tolochyn,1 O.V. Tolochyna,1 H.A. Bagliuk,1 Ya.I. Yevych,1 Yu.M. Podrezov,1,2 and A.A. Mamonova1 UDC 621.793+54-19 The paper examines the impact of heating temperature and isothermal holding time during sintering in a vacuum on the phase composition, structure, and mechanical properties of Fe3Al iron aluminide synthesized from a mixture of iron and aluminum powders. Dilatometric studies have shown the complexity of occurring changes in the density of the billets during sintering. First, the porosity increases from 15% in the initial billet to 45% during sintering at 950°C, and after decreases to 5% at a sintering temperature of 1450°C. The synthesis of intermetallic compounds at powder mixture heating was examined by the X-ray diffraction method. It was shown that up to 30% of intermetallic compound Fe2Al5 is formed during an hour-long isothermal holding at 600°C. Increasing the holding time to 3 hours or temperature to 950°C results in the formation and gradual growth of FeAl (B2) aluminide content. With a further increase of sintering temperature up to 1450°C, the amount of A2 phase becomes bigger, and concentration of iron and aluminum in it approaches to stoichiometric ratio Fe3Al. The mechanical properties of iron aluminide intensify with increasing sintering temperature, especially rapidly after sintering at 1450°C, when planar pores close and perfect interparticle contacts form. Keywords: intermetallic compound, iron aluminide, sintering, porosity, phase composition, strength, fracture toughness.
INTRODUCTION In recent years, growing interest among researchers and manufacturers has been drawn to Fe–Al intermetallic alloys due to their unique combination of physical, chemical, and mechanical properties such as low density, high corrosion resistance, heat resistance, and high-temperature strength [1–5]. Such a combination specifies the possibility of employing iron aluminides as functional and structural materials for operation at elevated temperatures and in aggressive media.
1Frantsevich
Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Kyiv,
Ukraine. 2To
whom correspondence should be addressed; e-mail: [email protected].
Translated from Poroshkova Metallurgiya, Vol. 59, Nos. 3–4 (532), pp. 42–54, 2020. Original article submitted December 26, 2019. 150
1068-1302/20/0304-0150 2020 Springer Science+Business Media, LLC
Along with unique physical and mechanical properties, these materials have relatively low cost and lower specific weight compared to steels, which allows its effective use in the automotive industry for the replacement of stainless steel in the exhaust system of cars, as valves and valve seats of automobile engines, for the disks of regenerators in automobile gas-turbine systems, etc. Fe–Al-based intermetallic compounds are also widely used for manufacturing rollers that transfer hot-rolled steel and as filters for coal g
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