Processing and Characterization of Bilayer Materials by Solid State Sintering for Orthopedic Applications

Abstract

A new processing route is proposed to produce graded porous materials by placing particles of Ti6Al4V with different sizes in different configurations to obtain bilayer samples that can be used as bone implants. The sintering behavior is studied by dilatometry and the effect of the layers’ configuration is established. To determine pore features, SEM and computed microtomography were used. Permeability is evaluated by numerical simulations in the 3D real microstructures and the mechanical properties are evaluated by compression tests. The results show that a graded porosity is obtained as a function of the size of the particle used. The mechanical anisotropy due to the pore size distribution and the sintering kinetics, can be changed by the particle layer arrangements. The Young modulus and yield stress depend on the relative density of the samples and can be roughly predicted by a power law, considering the layers’ configuration on the compression behavior. Permeability is intimately related to the median pore size that leads to anisotropy due to the layers’ configuration with smaller and coarser particles. It is concluded that the proposed processing route can produce materials with specific and graded characteristics, with the radial configuration being the most promising for biomedical applications.

Multi-Scale Modelling of the Bound Metal Deposition Manufacturing of Ti6Al4V

“…In addition, key mechanical properties of the sintered samples, such as microhardness, Young's modulus, and yield stress, can also be correlated with the fractional density [6,67]. Experimental data for the sintered Ti-6Al-4V samples collected in [6,68,69] are used to illustrate the latter correlations. These data can be fitted using Ashby correlations [67] of the polynomial type…”

“…Density is therefore one of the key fundamental properties of the samples that can provide a basis for developing a simple predictive model of nonlinear shrinkage, as will be discussed in more detail in the next section. [6,69] and the (right) panel shows the experimental data for yield stress [6,68,69] as a function of the relative density in each case. The following symbols are used in the left panel represent results from [68] and corresponds to [6]; while in the right panel - [6], - [69], - [68].…”

“…Mechanical properties of the sintered samples as a function of the relative density. The (left) panel shows experimentally obtained data for Young's modulus[6,69] and the (right) panel shows the experimental data for yield stress[6,68,69] as a function of the relative density in each case. The following symbols are used in the left panel represent results from[68] and corresponds to[6]; while in the right panel -[6], -[69], -[68].…”

“…The (left) panel shows experimentally obtained data for Young's modulus[6,69] and the (right) panel shows the experimental data for yield stress[6,68,69] as a function of the relative density in each case. The following symbols are used in the left panel represent results from[68] and corresponds to[6]; while in the right panel -[6], -[69], -[68]. The solid lines represent the results of fitting by correlations(18).…”