Novel strategy of planting nano-TiB fibers with ultra-fine network distribution into Ti-composite powder and its thermal transition mechanism

Abstract This work creatively planted nano-TiB fibers (10∼50 nm in width) as a novel ultra-fine network in pre-alloyed Ti-composite powder based on the rapid eutectic reaction method, constitutional supercooling would limit the ultra-fine network skeletons to micro-scale (2∼5 μm), which were thermal stabilized below 900 °C. The new configuration structure of ultra-fine network loaded the nano TiB-fibers is expected to improve the high temperature properties. However, high temperature would coarsen the nano-TiB fibers, resulting in the destruction of the ultra-fine network. The decomposition and growth of the TiB nano-fibers followed the Ostwald ripening mechanism and then coarsened following the merging mechanism, obtaining random distribution of two-scale TiB. It provided a new guidance for optimizing the nano-TiB size-scale and distribution by controlling the sintering temperature, which was useful for constructing multistage network structure enhanced Ti-composites based on pre-planted nano-TiB in alloy powders.