Electron Microscopy Study of the Eutectic Structure in Ti40Ni40Nb20 Alloy

• Published in: Materials Transactions, JIM Vol. 36; no. 1; pp. 23 - 29
• Main Authors: Onda, Tetsuhiko, Piao, Min, Bando, Yoshio, Ichinose, Hideki, Otsuka, Kazuhiro
• Format: Journal Article
• Language: English
• Published: Sendai The Japan Institute of Metals 1995; Japan Institute of Metals
• Subjects: Applied sciences; boundary structure; Cross-disciplinary physics: materials science; rheology; eutectic structure; Exact sciences and technology; high resolution electron microscopy(HREM); Martensitic transformations; Materials science; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; shape memory alloy; titanium-nickel; titanium-nickel-niobium; Eutectic alloy; Nickel alloys; Intermetallic compounds; Phase transformations; Ternary alloys; Niobium alloys; Experimental study; Electron microscopy; Orientation relation; Titanium alloys; Shape memory alloy; Shape memory effect; Microstructure; TEM; Martensitic transitions
• ISSN: 0916-1821; 2432-471X
• DOI: 10.2320/matertrans1989.36.23

The Ti40Ni40Nb20 eutectic is an interesting material with respect to the applications of shape memory alloys. The eutectic, which consists of TiNi(B2) α phase and Nb-rich(bcc) β phase, was studied by conventional and high resolution electron microscopy, and the following results were obtained. The morphology was invariably lamellar with the interface plane parallel to {110}α//{110}β. The orientation relationship was such that [100]α//[100]β [010]α//[010]β [001]α//[001]β Thus, the equivalent directions and planes are completely parallel. Steps and facets on a larger scale were found along the interfaces, and the Burgers vectors of misfit dislocations were analyzed by the O-lattice theory.