Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Grzegorz Cios"

Microstructure and phase composition characterization of a Ti–Al intermetallic alloy DOI:10.15199/28.2016.6.8

  Intermetallic Ti-Al alloys are characterized by the unique set of properties which makes these alloys a prospective material for the energy, automotive and aviation industries. The mechanical properties of a intermetallic alloys are strictly related to the microstructure. The refinement of the microstructure can be obtained by the manufacturing process, alloying additions and heat treatment. Microstructure characterization and knowledge about phase transformation mechanisms and their temperature ranges allows to change properties of the bulk material. The aim of this study was the microstructure and phase composition characterization of intermetallic Ti48Al2Cr2Nb alloy. The microstructure was examined using the light and scanning electron microscopy. Identification of phases and their temperature stability were determined by X-ray diffraction, differential dilatometry and calorimetry investigation. The oxidation process was determined by high temperature X-ray diffraction and the thermogravimetric method. The alloy after annealing has a duplex microstructure with precipitations of α2 phase in the γ matrix. Dilatometry and calorimetry allowed us to define the stability of each phase. At first the enriched in chromium α2 phase dissolved, after that the regions depleted in chromium were transformed, and above 775°C the microstructure was only the γ phase. Gamma phase was transformed above 1100°C, the end of transformation γ → α was evaluated as 1250°C. The oxidation investigations allowed us to show that the oxidation process started at 700°C by the oxide layer formation, which was stable till 900°C. Above this temperature the oxide layer started to grow. Key words: intermetallic alloy, microstructure, phase composition, Ti48Al2Cr2Nb, titanium alloy.1. INTRODUCTION Titanium intermetallic alloys due to their unique properties could find possible applications in a wide range of the industries, especially when th[...]

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