Micrometric grained Al synthesized via quasi-hydrostatic ultra-high pressure consolidation of micrometric Al powders

• Ultra-high pressure (UHP) can disrupt oxide films on powder surfaces.
• Micrometric grained (MMG) Al can be synthesized via UHP consolidation of Al powders.
• MMG Al synthesized via UHP consolidation exhibits high strength and ductility.

This paper reports a study on the synthesis of a fully dense micrometric grained (i.e., grain size around 1 μm) Al via consolidation of spherical micrometric-sized Al powders under a quasi-hydrostatic ultra-high pressure of 5 GPa. Our result shows that during consolidation oxide films on powder surfaces can be effectively disrupted into nano-scale oxide particles, which promoted the formation of metallurgical bonding between powders and the retention of micrometric-sized grains. Consequently, the as-consolidated Al is characterized by micrometric grains (average grain size of 1.2 μm) with a high density of nanoscale oxide particles (average size of ~25 nm) at grain boundaries. The as-consolidated Al exhibits both high strength (ultimate tensile strength of ~130 MPa) and ductility (uniform elongation of ~10%).