Microstructural characteristics of laser surface melted MoSiBTiC alloy

• Published in: Materials letters Vol. 278; p. 128465
• Main Authors: Higashi, Masaya, Ozaki, Tomomichi, Moronaga, Taku, Hara, Toru, Osada, Toshio, Kawagishi, Kyoko
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2020; Elsevier BV
• Subjects: Atom probe; Chemical composition; Electron microscopy; Heat affected zone; Lamellar structure; Materials science; Microstructure; Mo-Si-B alloy; Molybdenum; Selective laser melting; Solid solutions; Supersaturation; Titanium carbide; Ultrafines; Mo-Si-B alloy; Lamellar structure; Heat affected zone; Selective laser melting; Electron microscopy; Atom probe
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2020.128465

•Microstructures of laser surface melted MoSiBTiC alloy were characterized.•Microstructure inside a melt pool is composed of many cells with various sizes.•Each cell consists of an ultrafine ternary eutectic lamellar structure.•Lamellar structure completely disappears in a heat affected zone.•Atom probe tomography was used for detail microstructural characterization. The microstructural characteristics of a TiC-added Mo-Si-B (MoSiBTiC) alloy fabricated by laser surface melting were investigated. The microstructure inside a melt pool consisted of many cells, and each cell was composed of an ultrafine ternary eutectic lamellar structure with Mo solid solution (Moss), Mo5SiB2, and (Mo,Ti)2C phases. The lamellar structure completely disappeared in a heat affected zone (HAZ) formed by multi tracks test, and a fine round (Ti,Mo)C phase newly precipitated in the HAZ together with other phases. The chemical composition analyses identified the elemental supersaturation of Si and Ti in the Moss phase and of Ti in the T2 phase in the lamellar structure.