Vol.:(0123456789) 1 3 Metals and Materials International https://doi.org/10.1007/s12540-018-00223-w Analysis of Compression and Permeability Behavior of Porous Ti6Al4V by Computed Microtomography Luis Olmos 1  · Didier Bouvard 2  · Jose Luis Cabezas‑Villa 3  · Jose Lemus‑Ruiz 3  · Omar Jiménez 4  · Dante Arteaga 5 Received: 15 October 2018 / Accepted: 19 November 2018 © The Korean Institute of Metals and Materials 2018 Abstract Porous materials were developed as a good alternative to replace diferent bones in the human body as they improve osseoin‑ tegration, tissue ingrowth and simulate the mechanical properties of human bones. Such characteristics highly depend on the pore features and volume fraction. Samples with a pore volume fraction between 16 and 60% and a pore size distribution of 100–500 µm were analyzed by computed microtomography. 3D images acquisition was performed at 10 µm pixel resolution, which permitted to observe the complete sample. Features like size, shape, orientation, connectivity and pore coordination were determined from the 3D image analysis. Compression behavior was evaluated by interrupted compression testing and, after that, new 3D images were acquired. In order to evaluate permeability, numerical simulations of fow throughout the 3D images were carried out by using Avizo ® software. It was found that shape and pore size distribution was similar in all samples, showing good distribution of the pore formers inside the matrix. Full connectivity of pores was obtained with 32% volume fraction and above, and the coordination number follows the Artz model. The pores showed a radial orientation, which induces anisotropy in the fow properties. The compression showed two diferent behaviors, pore closing and pore coalescence. Values of permeability match with those reported for bones as well as the anisotropy in the radial and vertical directions. It is concluded that the sample with 60 vol% of pores could be consider to be used for bone implants. Keywords Porosity · Microtomography · Compression · Permeability · 3D image analysis 1 Introduction In the past years, the development of porous like scafolds materials has attracted many researches because of the necessity to produce bone implants [1, 2]. Diferent materi‑ als have been used to fabricate those kind of materials; from bioglass [3] to diferent metallic alloys [4–7]. Each material has advantages and disadvantages and they are chosen in regard to the location and characteristics of the bone to be replaced. Nowadays, there are some techniques to fabricate highly porous compacts, being additive manufacturing the most outstanding, but the most expensive among them [1, 2, 8]. On the other hand, the pore former process followed by a pressureless sintering represented a cheaper alternative to obtain highly porous compacts; it also allows to obtain a gradient porosity that mimics the real porosity in the bone [9–13]. There are a few characteristics that allow a bone implant to be successful: biocompatibility, osteoconductivity and mechanical mismatch of the elastic modulus. Biocompatibil‑ ity refers to the acceptance of the material inside the human body, which is intrinsically linked to the releasing of dan‑ gerous ions. Metallic alloys like stainless steel, CoCrMo, Ti alloys, Ta alloys, etc., have been studied demonstrating their biocompatibility [14]. The osteoconductivity on the other hand, is the ability of a porous implant to facilitate the bone grown through itself. For that, permeability plays a major role as it favors the pass of nutrients and minerals to the * Luis Olmos luisra24@gmail.com 1 INICIT, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán C.P. 58060, Mexico 2 SIMaP, Univ. Grenoble Alpes, CNRS, 38000 Grenoble, France 3 IIMM, Universidad Michoacana de San Nicolás de Hidalgo, Fco. J. Mujica S/N, Ed. C‑2 C.U., Morelia, Michoacán C.P. 58060, Mexico 4 Departamento de Ingeniería de Proyectos, Universidad de Guadalajara, Zapopan, Jalisco 45100, Mexico 5 Centro de Geociencias, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico