Influence of Magnesium Infiltration on Compressive Behavior of Additively Manufactured Porous Ti6Al4V Structure

As the next generation of metallic implants, Ti6Al4V porous structures have captivated more attention; however, the primitive compressive strength of the Ti6Al4V material is drastically reduced in its porous form while matching its Young's modulus with that of the bone to avoid `stress-shielding effect'. This work sheds light on an unconventional approach to develop a metallic implant that addresses the twin demands of having high compressive strength and low Young's modulus matching with that of the bone. This study focuses exclusively on the compressive behavior because most of the implants like hip and knee prosthesis are subjected to compressive loading. Porous Ti6Al4V structures with porosity ranging from 60-75 % are fabricated using electron beam melting, an additive manufacturing technique. And then, a pressureless infiltration technique is carried out to infiltrate pure magnesium, a good biodegradable material, into the porous structures by casting process. The compressive behavior of the infiltrated structures is analyzed and compared with porous Ti6Al4V structures. The compressive strength of the porous Ti6Al4V structures is enhanced up to 200 % after infiltrating it with biodegradable magnesium without much change in the modulus, making it a good candidate for the biomedical metallic implants. Moreover, the stress-strain characteristics of the magnesium-infiltrated Ti6Al4V samples exhibited ductile nature when compared with the stress-strain curves of the porous Ti6Al4V samples, which showed brittle nature, thereby enhancing the energy-absorbing quality of the metallic implant.