Electroshock treatment dependent microstructural evolution and mechanical properties of near-β titanium alloy manufactured by directed energy deposition. (15th December 2021)

• Record Type: Journal Article
• Authors: Guo, Haojie; Liu, Pu; Qin, Xunpeng; Song, Yanli; Qian, Dongsheng; Xie, Lechun; Wang, Liqiang; Zhang, Lai-Chang; Hua, Lin
• Is Part Of: Materials & design. Volume 212(2021)
• Publication Date: 2021-12-15
• Subjects: Electroshock treatment (EST) -- Directed energy deposition (DED) -- Near-β titanium alloy -- Microstructure -- Mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2021.110286
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Texture intensity decreased due to the uniform distribution of α phase after EST. The average hardness of specimen decreased but the ductility was enhanced after EST. TEM results indicated that the α phase was distributed uniformly after EST with 0.03 s. After EST, more atom vacancies and lattice distortion were formed near α/β interfaces. Atom vacancies and lattice distortion could reduce hardness and improve ductility. Abstract: Effects of electroshock treatment (EST) on the microstructural evolution and mechanical properties of near-β titanium alloy (Ti-55531) formed by directed energy deposition (DED) was studied in this work. With the increase in EST time, the average hardness of specimen decreased from 426 HV to 316 HV, and the fracture strain increased significantly, which was attributed to the uniform dispersion of α phase along grain boundaries and inside the β grains. After EST, the texture intensity decreased in terms of the orientation distribution function (ODF), which was ascribed to the redistribution of α phase. Moreover, more atomic vacancies and lattice distortion were formed near the α/β interfaces, which were verified by transmission electron microscopy (TEM) observation and ascribed to the migration of atoms near the interface under EST. External loadings facilitated the dislocation motion and lattice distortions near the interfaces, which resulted in the reduction in hardness and the improvement in ductility. The above results indicated that EST can quickly alter the microstructure and mechanical properties of DED titanium alloys as a simple and energy-saving method.