Ermüdungseigenschaften von additiv gefertigten Titanstrukturen im Hinblick auf den Einsatz im menschlichen Körper

Abstract

The additive manufacturing process Selective Laser Melting (SLM) is well suited for economic production of complex and individual parts in small batches (e.g. hip implants). The melting system in this work was used to process parts consisting of the high-strength and biocompatible titanium alloy Ti-6-4. The presence of the cyclic loadings within the human body requires investigations in terms of the crack growth behavior and the resulting lifetime of the product. For that purpose, fatigue crack growth rate data for various material conditions were obtained in experiments. Based on these information numerical studies regarding crack growth and lifetime of the hip implant, in the as-built and heat treated condition, were performed. It was found that the significant improvement of the fatigue crack growth performance and the increase of the lifetime of a pre-cracked part can only be achieved by elimination of residual stresses using heat treatments.