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Microstructure evolution and its effect on mechanical response of the multi-phase reinforced Ti-based composites by laser powder-bed fusion
- Source :
- Journal of Alloys and Compounds. 782:506-515
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- The Ti-based composites reinforced by in-situ formed TiB and TiC particles were successfully produced by laser powder-bed fusion (LPBF) additive manufactured technology using a B4C/Ti composite powder mixture, in order to further enhance the mechanical properties of commercially pure titanium (CP-Ti). The effects of applied laser energy density on the microstructure and attendant mechanical properties of the LPBF-processed parts were investigated, and meanwhile, the underlying formation mechanisms of the TiB and TiC particles by LPBF were elucidated. It showed that the whisker-like TiB and near-granular TiC reinforcements were in-situ formed through a laser-induced reaction of Ti-B4C system via a diffusion-nucleation-growth mechanism from the melt. The in-situ reinforcements arranged from dendrite to cellular morphology were primarily determined by the thermal convections that transformed from dendrite to annular patterns as a result of the great elevation of temperature gradient between molten Ti liquid and heated B4C particles as an increase in the applied laser energy density. The tensile tests revealed that the LPBF-ed Ti-based composites possessed an enhanced tensile strength from 893 ± 5 MPa to 1211 ± 8 MPa and a slightly reduced elongation from 18.1% to 16.8% with the transition of typically fracture morphologies from elongated dimples to equiaxed-ultrafine dimples, respectively, attributed to the combined grain refinement and microstructure strengthening effects.
- Subjects :
- Fusion
Materials science
Mechanical Engineering
Composite number
Metals and Alloys
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Microstructure
01 natural sciences
0104 chemical sciences
Temperature gradient
Dendrite (crystal)
Mechanics of Materials
Ultimate tensile strength
Materials Chemistry
Composite material
Elongation
0210 nano-technology
Powder mixture
Subjects
Details
- ISSN :
- 09258388
- Volume :
- 782
- Database :
- OpenAIRE
- Journal :
- Journal of Alloys and Compounds
- Accession number :
- edsair.doi...........ea7d94529f9e533007d1a8abfaee53ab