No abstract

Selective Laser Melting (SLM) is known to cause residual stresses due to the inherent large thermal gradients from high heating and cooling rates during manufacturing. The residual stresses tend to induce distortion, delamination of parts from the base plate as well as cracking because they reduce the threshold flaw size required for crack initiation. These challenges form a barrier to the use of this additive manufacturing method for structural applications for the aerospace industry where high part integrity is a critical requirement. The aim of the study was to evaluate the degree of distortion and crack growth resistance during increasing monotonic loading and cyclic loading of As-built Ti6Al4V parts produced on the Aeroswift high speed SLM process preheated at 200°C. The monotonic loading results are comparable to those of commercial SLM systems but are lower when compared conventional manufacturing methods. The crack growth resistance of the As-built specimen is lower than that of heat treated specimen. Distortion at this preheating temperature is evident at from 12cm away from the base of the cantilever and spreads to height of 3.2mm.

Middle ear surgeries involve Total Ossicular Replacement Prosthesis (TORP) or Partial Ossicular Replacement Prosthesis, where all or some of the three ossicle bones are replaced. Current prostheses are dissimilar to the natural ossicles in geometry, size and only recover up to 75% sound transmission. Additive manufacturing offers complex, near-net shape geometries that allow for patient specific implants. A novel design is used to manufacture a TORP in Ti6Al4V(ELI) via Additive Manufacturing. The sound transmission level of the of the additively manufactured titanium prosthesis was measured by laser doppler vibrometry and compared to that of a Silver additively manufactured prosthesis. The sound transmission level of the additively manufactured prostheses are also compared to that of the international standards and literature using this method.