Microstructure and tensile properties of as-cast Ti–45Al–(8–9)Nb–(W, B, Y) alloy
2005; Elsevier BV; Volume: 414; Issue: 1-2 Linguagem: Inglês
10.1016/j.jallcom.2005.02.110
ISSN1873-4669
AutoresXiangyu Xu, J.P. Lin, Y.L. Wang, Jingyuan Gao, Zhi Lin, G.L. Chen,
Tópico(s)Aluminum Alloy Microstructure Properties
ResumoMicrostructure and tensile properties of high Nb containing TiAl alloy, with nominal composition of Ti–45Al–(8–9)Nb–(W, B, Y) (at.%), were investigated. The results showed that the as-cast alloy had near lamellar microstructure composed of fine homogenous lamellar colonies, with a size of about 70 μm, and a small amount of β phase and equiaxed γ phase. The β phase existed either on the boundaries of the lamellar colonies in irregular morphology or in the lamellar colonies in lamellar or blocky morphology. Equiaxed γ phase existed on the boundaries of lamellar colonies. There also existed some borides in three morphologies: convoluted flakes, ribbons and particles. The alloy had mediate tensile properties at both room temperature (RT) and high temperature. At RT, ultimate tensile strength level of 668 MPa and 0.49% plastic elongation were obtained, and the brittle-to-ductile transition temperature was higher than 815 °C. Cracks propagated in transgranular mode predominantly, and borides and β phase were detrimental to the ductility of the as-cast alloy.
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