Characteristics and structure of porous TNM alloy for biomedical applications

Abstract

In this study, a biomedical porous Ti–5Nb–5Mo (TNM) alloy was fabricated by mechanical alloying (MA), with ball milling times of 3 h, 15 h and 30 h. The particle sizes of Ti–5Nb–5Mo increased as the milling times increased from 3 h (35 μm) to 15 h (72 μm). The ball milling process produced alloy particles that gathered together, resulting in a larger overall particle size. The ball milled Ti–5Nb–5Mo particles were significantly refined, and Nb and Mo were integrated into and uniformly distributed within the matrix. XRD analysis showed that the porous Ti–5Nb–5Mo sample was composed of α phase. The compressive strength and modulus of all the porous Ti–5Nb–5Mo sample matched the necessary mechanical properties of cancellous bones; in particular, the B3S15 specimen (balling 3 h and sintering 10 h) had the highest strength and was selected for bioactivity and cytocompatibility testing. After soaking in a simulated body fluid for 4 days, the alkali-heat treated porous B3S10 alloy formed a dense apatite layer on its surface. The specimen exhibited better apatite-forming ability, and its surface proved beneficial to the spread, proliferation, and differentiation of osteoblast-like cells. This result confirms that both a porous structure and alkali heat treatment are favorable for cell growth. Most importantly, this study reveals that porous TNM satisfies the requirements demanded by an implant material: an adequate mechanical strength and elastic modulus, and good biocompatibility.