Nanoparticle dispersion effect of laser-surface melting in ZrB2p/6061Al composites
Zirconium diboride (ZrB2p, 15 vol%)/6061 aluminum (Al) composites were fabricated via in situ reaction. The existence, morphologies, and dispersion degree of the in situ ZrB2 particles with size from tens to hundreds of nanometers were studied by X-ray diffractometry, energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. As the particle-settlement effect becomes dominant during the composite fabrication process, ZrB2 nanoparticles agglomerate to a certain extent in some areas of the as-cast composites. A laser-surface melting (LSM) strategy was applied to disperse agglomerated ZrB2 nanoparticles in as-cast composites, and the ZrB2 nanoparticle dispersion is affected visibly by LSM. After LSM, nanoparticles tend to distribute along the grain boundary. Particle clusters were dispersed in an explosive orientation and the particle diffusion distance varied in terms of its radius and melt-viscosity vicinity. High-resolution transmission electron microscopy showed the existence of a subgrain structure near the ZrB2–Al interface after LSM. This may increase the yield strength when a dislocation tangle forms.
KeywordsLightweight metals Laser-surface melting ZrB2p/6061Al composite Orientation-dispersed nanoparticle Subgrain structure
This work was supported by the National Natural Science Foundation of China (Grant Nos. 51405334 and 51275342), State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology (AWJ-Z14-03).
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Conflict of interest
The authors declare that they have no conflict of interest.
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