Interphase boundary precipitation in a Ti-1.7 at. pct Er alloy

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 28; no. 12; pp. 2485 - 2497
• Main Authors: KRAL, M. V, HOFMEISTER, W. H, WITTIG, J. E
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01.12.1997; Springer Nature B.V
• Subjects: Allotropy; Alloy steels; Alloys; Annealing; Applied sciences; Cross-disciplinary physics: materials science; rheology; Crystallography; Electron diffraction; Erbium base alloys; Erbium oxide; Exact sciences and technology; Growth models; Materials science; Metals. Metallurgy; Morphology; Phase boundaries; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precipitates; Precipitation; Rapid solidification; Sheets; Solid-phase precipitation; Titanium base alloys; Crystal orientation; Electron diffraction; Grain boundary precipitation; Experimental study; Erbium alloys; Phase transitions; Titanium base alloys; Habit plane; Binary alloys; Precipitation; Transition elements; Phase boundaries; Rapidly solidified alloy; Microstructure; TEM
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-997-0006-9

Microstructures in a Ti-1.7 at. pct Er alloy were studied in the arc-cast, rapidly solidified, and annealed conditions. Transmission electron microscopy (TEM) of the rapidly solidified materials revealed 3- to 20-nm-diameter precipitates that were distributed in regularly spaced, approximately planar sheets throughout equiaxed α Ti grains. The precipitate sheet morphology is similar to the interphase boundary carbide sheets that have been documented in many alloy steels. In addition, precipitate fibers with cross sections of approximately 5 nm and up to 500 nm in length were often found adjacent to particle sheets. Electron diffraction experiments showed that the structure and lattice spacings of the sheet and fibrous particles are consistent with elemental erbium. Subsequent annealing treatments resulted in the formation of a face-centered cubic allotrope of Er2O3. The present work describes the precipitate morphologies and crystallography and discusses the applicability of current ledge growth models of interphase boundary precipitation to titanium-erbium alloys.