*Magnesium in Synthesis of Porous and Biofunctionalized Metallic Materials DOI: http://dx.doi.org/10.5772/intechopen.102083*

other elements to form porous alloys such as Ti can be an interesting alternative. For the production of porosity using this technique, it is necessary to control parameters such as temperature and times of the sintering steps, in addition to the particle size of the powders, due to its commitment to mechanical properties [52]. Such variables strongly influence the morphology of the pores, that is, it can provide the same amount of porosity, but with different shapes and sizes. The mechanical properties are also affected, mainly those related to the ductility and dynamic properties of the material, as they depend on the porosity characteristics [53]. The pores attenuate the applied force, do not distribute it over a larger area and cause local stress accumulation, so that they can even serve as sites for crack nucleation [54]. The effect of porosity on mechanical properties depends mainly on the following factors: volume fraction of the pores and their interconnection, size, morphology and distribution. The most important parameters are the total porosity, the shape of the pores and/or contacts during sintering [55].

Porosity has a noticeable and well-recognized effect on mechanical properties. Porosity can increase stress concentration and cause fractures. It was demonstrated by Danninger et al. that this parameter is directly related to the mechanical properties of an alloy [56]. These factors can be controlled by adjusting the sintering parameters, compaction pressure and particle size [57]. Optionally, functional porosity can be introduced by adapting the particle size of the starting powders and the sintering conditions. In addition, powder metallurgy allows flexibility in alloy design, mixing pure Mg powders with different elemental or alloy powders. Due to the high affinity of Mg for oxygen, all handling of powders and samples, as well as subsequent sintering, must be carried out under a protective atmosphere of argon or under vacuum [58] conditions, residual pores can vary between 2% and 45%. When approaching porosities close to 45%, interconnection (percolation) of the pores appears.
