Effects of Porosity on Mechanical Properties and Corrosion Resistances of PM-Fabricated Porous Ti-10Mo Alloy

Abstract

Porous binary Ti-10Mo alloys were prepared using non-spherical titanium, molybdenum powders by the powder metallurgy (PM) space holder technique. Based on the three-dimensional analysis of porosity characteristics, a detailed assessment of the effects of porosity on mechanical properties and corrosion resistances in phosphate-buffered saline (PBS) was carried out. For comparison, PM-fabricated CP-Ti with 50.5% porosity sintered at 1200 • C for 2 h and dense Ti-10Mo alloy sintered at 1450 • C for 2 h (relative density is 97.2% and porosity is 2.8%) were studied simultaneously. The results show that with the space-holder volume contents rising from 63 to 79%, the open porosity and average pore size (d 50) increase remarkably, while the pore size distribution (d 10-d 90) tends to be stable at about 100 µm. The average pore sizes (d 50) of porous Ti-10Mo alloy can be controlled in the range of 70-380 µm. The PM-fabricated porous Ti-10Mo alloy can achieve a wide range of mechanical properties, with yield compression strength of 248.2-76.9 MPa, and elastic modulus of 6.4-1.7 GPa. In addition, the yield compression strength and the elastic modulus meet the linear regression and exponential formula, respectively. With the porosity of Ti-10Mo alloy increasing from 2.8 to 66.9%, the corrosion rate rises exponentially from 1.6 g/m 2 •day to 17.1 g/m 2 •day. In comparison to CP Ti with nearly the same porosity, Ti-10Mo alloy shows significantly higher corrosion resistance. As a result, the relationships between porosity and mechanical properties, corrosion resistances of Ti-10Mo alloys were established, which can be used as a design reference in material selection for orthopedic applications.

The Effect of Electrophoretic Deposition Parameters on the Microstructure and Adhesion of Zein Coatings to Titanium Substrates

“…This result can be strongly connected with the presence of open pores with relatively high diameter up to 25 μm ( Figure 17 ), which lead to easy penetration of the corrosive environment into the coating and cause damage. Xu et al [ 57 ] showed that the rise of porosity inevitably deteriorates the corrosion resistance, and accordingly, the corrosion rate of the porous Ti-10Mo alloy increases exponentially. In order to improve coating quality, particularly to avoid the formation of open porosity in the coating resulting from water electrolysis, and thus to enhance the electrochemical corrosion resistance of the titanium coated with zein, further research will be focused on using pulsed direct current (PDC) and alternating current (AC) electrophoretic deposition.…”

Porous Ti-10Mo alloy fabricated by powder metallurgy for promoting bone regeneration

“…The Ti-10Mo powder mixtures were blended with space-holder particles (ammonium hydrogen carbonate, NH 4 HCO 3 ) for 3 h, and then was cold-pressed into a cylindrical compact under 260 MPa. Finally, the isothermal sintering was carried out in the argon (Ar) protection environment at 1,300°C for 2 h. The detailed fabricating process is available in our previous study [33].…”

“…Then the slice images were input into the Avizo software to be reconstructed. The total porosity, connected porosity and average pore sizes of the specimens were calculated by Avizo, as described in our previous study [33]. X-ray diffraction (XRD) for phase analysis was conducted with a Dmax-RB X-ray diffractometer (Cu Kα, λ=0.15406 nm, Rigaku, Tokyo, Japan).…”

Design and performance evaluation of additively manufactured composite lattice structures of commercially pure Ti (CP–Ti)

“…But these studies mainly focus on single lattice structures that cannot match the natural bones well at the strength and elastic modulus. Thus, from a design point of a view, it is imperative to design porous Ti scaffolds with different pore porosities and pore sizes, in order to match the mechanical and biological properties of natural bone [ [24] , [25] , [26] , [27] ].…”