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Formation of a bimodal structure in ultrafine Ti-Fe-Nb alloys with high-strength and enhanced ductility

TitleFormation of a bimodal structure in ultrafine Ti-Fe-Nb alloys with high-strength and enhanced ductility
Publication TypeJournal Article
Year of Publication2014
AuthorsCao, GH, Peng, YF, Liu, N, Li, X, Lei, ZS, Ren, ZM, Gerthsen, D, Russell, AM
JournalMaterials Science and Engineering a-Structural Materials Properties Microstructure and Processing
Volume609
Pagination60-64
Date Published07
Type of ArticleArticle
ISBN Number0921-5093
Accession NumberWOS:000338806200008
Keywordsbulk alloys, characterization, Electron microscopy, Eutectics, large, Mechanical, mechanical-properties, metals, Microstructure, nanostructure-dendrite composite, Nanostructured materials, phase, plasticity, sn, Titanium alloys
Abstract

Bulk (Ti(70.5)Fe29.5)(100-x)Nb-x (x=0, 3, 5 and 7 at%) alloys were prepared by cold crucible levitation melting, and their mechanical properties were tested in compression at room temperature. A (Ti70.5Fe29.5)(97)Nb-3 alloy specimen in compression exhibited an ultimate compressive strength of 2.53 GPa and a compressive plastic strain of 15%. Electron microscope observations indicated that lamellar structures present in the eutectic Ti70.5Fe29.5 alloy could be modified by the addition of Nb to obtain a bimodal structure. The improvement of the mechanical properties is attributed to two factors: (1) the bimodal phase size distribution with micrometer-sized primary beta-Ti dendrites embedded inside a matrix of refined ultrafine eutectics (beta-Ti+TiFe), and (2) the larger lattice mismatches between the beta-Ti and TiFe phases in Nb-modified eutectic Ti-Fe alloys that introduce coherency strain at the interface. The orientation relationship of A2 beta-Ti with B2 TiFe in binary and Nb-modified Ti-Fe alloys is TiFe (110)[001] II beta-Ti (110)[001]. (C) 2014 Elsevier B.V. All rights reserved.

DOI10.1016/j.msea.2014.04.088
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