Strengthening porous titanium fabricated by powder metallurgy via multi-step pressing technique

Conventional porous titanium suffers from insufficient strength and imprecise pore control. This work improved powder metallurgy process by employing a multi-step pressing (MSP) process with NH 4 HCO 3 space holder to enhance pore structure and mechanical properties. Compared with one-step pressing (OSP), the MSP process significantly reduces microporous defects within pore walls and improves pore uniformity, sphericity, and large pore proportion. Thus, the MSP process effectively increases the load-bearing area of the pore wall via decreasing micropore defects and reduces stress concentration through enhancing the pore sphericality. This mechanism plays a crucial role in enhancing the strength of porous titanium. With 50% NH 4 HCO 3 addition, the porosity of the MSP sample reached 51.9% and achieved elastic modulus of 6.9 GPa and compressive strength of 85 MPa, representing a 1.9% porosity reduction and 9.0% strength increase compared with OSP sample. MSP-produced porous titanium exhibited controllable porosity (24.9–51.9%), elastic modulus (6.9–16.0 GPa) and compressive strength (85–178 MPa). These tailored properties closely match those of human bone, offering a promising strategy for high-performance medical implants. • A multi-step pressing (MSP) process combining with NH 4 HCO 3 as a space holder is developed to fabricate porous titanium with enhanced pore structure and mechanical strength. • MSP significantly reduces microporous defects and improves pore sphericity, leading to a 9.0% increase in compressive strength while maintaining a bone-matching elastic modulus. • MSP-produced porous titanium exhibits controllable porosity (24.9%–51.9%), elastic modulus (6.9–16.0 GPa), and compressive strength (85–178 MPa), closely matching the properties of human bone for biomedical implants.