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Effect of boron on the microstructure and mechanical properties of Ti-6Al-4V produced by laser directed energy deposition after heat treatment.
- Source :
- Journal of Laser Applications; Feb2020, Vol. 32 Issue 1, p1-10, 10p
- Publication Year :
- 2020
-
Abstract
- The nearly rapid solidification and high-temperature thermal cycles associated with laser directed energy deposition of titanium alloys using laser solid forming (LSF) lead to the formation of coarse prior β columnar grains and continuous coarse-grain-boundary α (α<subscript>GB</subscript>) phases, which result in anisotropic properties and poor ductility. The influence mechanisms of trace B (up to 0.3 wt. %) on the solidification, solid state transformation, and tensile properties of LSFed Ti-6Al-4V after solution and aging treatment were studied using thermodynamic calculations. With an increase in B content, the size of prior β grains decreased owing to the growth-restricting effect it caused during the solidification and the Zener pinning caused by TiB during reheat cycles and heat treatments. The continuous coarse α<subscript>GB</subscript> phases were almost eliminated owing to the discontinuous distribution of TiB between the dendrites, and the length and aspect ratio of intragranular α phases were gradually reduced. Moreover, both ultimate tensile strength and yield strength increased, fracture elongation decreased, strength anisotropy decreased, and elongation anisotropy initially increased and then decreased significantly. The findings in this study will promote the development of new Ti alloys befitting additive manufacturing technology. [ABSTRACT FROM AUTHOR]
- Subjects :
- BORON
MICROSTRUCTURE
MECHANICAL behavior of materials
LASERS
HEAT treatment
Subjects
Details
- Language :
- English
- ISSN :
- 1042346X
- Volume :
- 32
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Journal of Laser Applications
- Publication Type :
- Academic Journal
- Accession number :
- 142009858
- Full Text :
- https://doi.org/10.2351/1.5098074