Influence of the Compaction Pressure and Sintering Temperature on the Mechanical Properties of Porous Titanium for Biomedical Applications

Abstract

In the present work, the use of porous titanium is proposed as a solution to the difference in stiffness between the implant and bone tissue, avoiding the bone resorption. Conventional powder metallurgical technique is an industrially established route for fabrication of this type of material. The results are discussed in terms of the influence of compaction pressure and sintering temperature on the porosity (volumetric fraction, size, and morphology) and the quality of the sintering necks. A very good agreement between the predicted values obtained using a simple 2D finite element model, the experimental uniaxial compression behavior, and the analytical model proposed by Nielsen, has been found for both the Young’s modulus and the yield strength. The porous samples obtained by the loose sintering technique and using temperatures between 1000 °C −1100 °C (about 40% of total porosity) are recommended for achieving a suitable biomechanical behavior for cortical bone partial replacement.

Porous Titanium Cylinders Obtained by the Freeze-Casting Technique: Influence of Process Parameters on Porosity and Mechanical Behavior

“…Considering the advantages and disadvantages of the experimental techniques to evaluate the Young's modulus of porous material, in this work, it has been evaluated following the two methods above mentioned (uniaxial compression test and ultrasounds technique), obtaining a higher value by ultrasounds than compression test (35 GPa vs 19 GPa, respectively). It has been previously reported by some of authors of this work [33,34,37,38] that there is a discrepancy between the value obtained by applying both experimental techniques. In Ni-Ti materials, this difference in the measured values is related to a super-elastic deformation within the linear-elastic range; it has been observed that, by the ultrasound technique, stiffness decreases for higher porosity values, according to the elastic Eshelby-based theory for closed, spherical porosity [39].…”

Caracterización de CP-Titanio producido mediante inyección aglutinante y pulvimetalurgia convencional

“…It is observed that pores of the specimens produced with uniaxial press method have a spherical morphology and shrink with the increase of compression pressure. The compression pressure applied to the powder material enables the small irregular pores to combine and hence lead to a reduction of the large-sized pores (Amidon et al, 2017;Castillo et al, 2019). It is seen that the pores of specimens fabricated by 3D printer are non-uniform and exist in different sizes.…”

“…It is seen that the pores of specimens fabricated by 3D printer are non-uniform and exist in different sizes. In the Binder Jetting method, pores are non-uniform due to the lack of compression pressure, the droplet effect of the liquid binder and, the accumulation of binder between particles (Kunchala and Kappagantula, 2018;Stevens et al, 2018;Castillo et al, 2019).…”

“…These problems can be minimized by producing porous implants with similar mechanical properties to bone tissue. Porous Ti implants with low density can be manufactured by conventional powder metallurgy method and additive manufacturing techniques (Wiria et al, 2010;Goia et al, 2013;Tojal et al, 2013;Yang et al, 2018;Yılmaz et al, 2018;Castillo et al, 2019).…”

“…Although this method is fast and economical to produce a large number of small and uncomplicated parts, the cost and time of production are high for producing complex and low quantity of patient-specific implants. In this method, powder material properties, compression pressure, and sintering conditions directly affect the density and mechanical properties of the final products (Esteban et al, 2011;Castillo et al, 2019;Cuesta et al, 2019).…”