Microstructure and Phase Composition of VT1-0, VT6, and VT14 Titanium Alloys Produced by Wire-Feed Electron-Beam Additive Manufacturing

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques x-ray, synchrotron and neutron techniques, 2022-12, Vol.16 (6), p.983-991
• Main Authors: Panin, A. V., Kazachenok, M. S., Kazantseva, L. A., Martynov, S. A., Panina, A. A., Lobova, T. A.
• Format: Article
• Language: English
• Subjects: Alloying effects; Alloying elements; Aluminum; Atomic structure; Beta phase; Chemistry and Materials Science; Electron backscatter diffraction; Electron beams; Electronic structure; Lattice parameters; Martensite; Materials Science; Microstructure; Phase composition; Residual stress; Surfaces and Interfaces; Thin Films; Titanium alloys; Titanium base alloys; Wire
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S1027451022060180

Using optical, scanning- and transmission-electron microscopy, and also electron backscatter diffraction, we demonstrate that the microstructure of samples of commercially pure titanium VT1-0 and titanium alloys VT6 and VT14, obtained by the wire-feed electron-beam additive method, consists of columnar primary grains of the β phase of titanium containing crystals of packet and lamellar martensite phases. Х-ray diffraction phase analysis shows that the concentration of the residual β phase in the VT6 and VT14 samples is 2.9 and 10.5%, respectively. The concentration of alloying elements in the α and β phases of titanium alloys is measured by energy-dispersive analysis. The effect of alloying elements on the lattice parameters of the α phase of the samples is demonstrated. The different concentration of the residual β phase in titanium alloys VT6 and VT14 can be explained by considering the electronic structure of atoms of alloying elements. Tensile residual stress is present in samples VT1-0, while the residual stress in samples VT6 and VT14 is compressive. The presence of aluminum in the titanium alloys affects the sign and magnitude of the residual stress in titanium-alloy samples.