Superior role of LaB6 in enhancing O-scavenging efficiency during sintering Ti alloy from electrostatic self-assemble LaB6-coated Ti powder

LaB6 has been demonstrated as an effective O-scavenger for powder metallurgy (PM) Ti alloys to mitigate the detrimental effect of solid-solution O on the ductility. However, conventional mechanical mixing methods lead to the agglomeration and non-uniform distribution of LaB6, resulting in partial deactivation and reduced O -scavenging efficiency during sintering. Aiming at this issue, we propose an electrostatic self-assembly strategy that combined surface functional modification of LaB6 with solid-liquid fluidized bed powder coating treatment to synthesize a novel LaB6-coated Ti composite powder. Compared to traditional LaB6 additives in powder mixtures, the LaB6-coating particles exhibited excellent O-scavenging efficiency and higher utilization rate. Even at a low coating-content of 0.3 wt% LaB6, the tensile strength and elongation of the as-sintered Ti samples increased from 461 +/- 26 to 579 +/- 13 MPa and 5.6 +/- 1.4% to 14.2 +/- 0.3%, respectively. The achieved improvement rate (-95%) in tensile elongation was significantly superior to the previously reported data of the rare-earth O -scavengers.