Structure-property orientation relationship of a gamma/alpha(2)/Ti5Si3 in as-cast Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy

MN Mathabathe and AS Bolokang and G Govender and RJ Mostert and CW Siyasiya, JOURNAL OF ALLOYS AND COMPOUNDS, 765, 690-699 (2018).

DOI: 10.1016/j.jallcom.2018.06.265

Structure-property relationship of the as-cast gamma-Ti-45Al- 2Nb-0.7Cr-0.3Si based intermetallic alloy was examined. The phases stable at room temperature in the alloy were gamma/alpha(2)/Ti5Si3, respectively; while their crystal structures were described by means of chemical formulas, Pearson's number, space groups, lattice parameters, atomic positions and occupancy numbers using a Vienna ab initio simulation package (VASP) software for materials design. Moreover, high resolution electron backscatter diffraction (HSEBSD) was used to analyse the orientation relationship of both the as-cast (beta-solidifying) and heat-treated (alpha-solidifying) microstructural phases. The results showed that the formation of gamma/alpha(2)/Ti5Si3 follows the Blackburn orientation relationship (BOR): (beta-solidifying) 110(beta)//0001(alpha) and <111>(beta)//<2(-)1(-)10>(alpha), and for (alpha-solidifying) = (111)gamma parallel to (0001)alpha and <1(-)10gamma parallel to <11(-)20>alpha. (C) 2018 Elsevier B.V. All rights reserved.

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