Fatigue behavior of thin-walled grade 2 titanium samples processed by selective laser melting. Application to life prediction of porous titanium implants.

摘要: Because of its biocompatibility and high mechanical properties, the commercially pure grade 2 titanium (CPG2Ti) is largely used for fabrication patient specific implants or hard tissue substitutes with complex shape. To avoid stress-shielding help their colonization by bone, prostheses a controlled porosity are designed. The selective laser melting (SLM) well adapted to manufacture such geometrically complicated structures constituted struts rough surfaces relatively small diameters. Few studies were dedicated characterize fatigue properties SLM processed samples bulk parts. They followed conventional standard protocols. behavior very different from one porous raw structures. In this study, made "as built" (AB) "heat treated" (HT) tubular tested in fatigue. Wohler curves determined both cases. obtained endurance limits equal σD(AB)=74.5MPa σD(HT)=65.7MPa, respectively. heat treatment worsened limit relaxation negative residual stresses measured on external surface samples. Modified Goodman diagram was established specimens. Porous samples, based pattern developed Barbas et al. (2012), manufactured SLM. Fatigue tests finite element simulations performed these enabled determination simple rule assessment. method stress gradient appeared as best approach take into account notch influence life CPG2Ti porosity. direction dependent apparent strength found. A criterion effective, global, nominal proposed taking anisotropy Thanks criterion, usual calculation methods can be design bone substitutes, without precise modelling internal fine