Microstructures evolution and physical properties of laser induced NbC modified nanocrystalline composites

•Ultrafine nanocrystals, quasicrystals, amorphous were produced in such laser clad hard composites.•Portion of amorphous was resolved into nanoscale particles included in icosahedral quasicrystals.•A portion of the amorphous phases could be resolved into icosahedral quasicrystals.•Ultrafine nanocrystals can also intertwin with amorphous, forming yarn-shape materials.

The nanoscale quasicrystals (NQs), amorphous and ultrafine nanocrystals (UNs) modified hard composites are produced by laser cladding (LC) of the Ni60A-TiC-NbC-Sb mixed powders on the additive manufacturing (AM) TA1 titanium alloy. The LC technique is favorable to formations of icosahedral quasicrystals (I-phase) with five-fold symmetry due to its rapid cooling and solidification characteristics. The formation mechanism of this I-phase is explained here. Under the actions of NQs, amorphous and UNs, such LC composites exhibited an extremely high micro-hardness. UNs may also intertwin with amorphous, forming yarn-shape materials. This research provides essential theoretical basis to improve the quality of laser-treated composites.