Browsing by Author "Buciumeanu, M."
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- 316L stainless steel mechanical and tribological behavior—A comparison between selective laser melting, hot pressing and conventional castingPublication . Bartolomeu, F.; Buciumeanu, M.; Pinto, E.; Alves, Nuno; Carvalho, O.; Silva, F: S.; Miranda, G.This work presents a comprehensive study on the influence of three different processing technologies (Selective Laser Melting, Hot Pressing and conventional casting) on the microstructure, mechanical and wear behavior of an austenitic 316L Stainless Steel.Acorrelation between the processing technologies,the obtained microstructure and the mechanical and wear behavior was achieved. The results showed that the highest mechanical properties and tribological performance were obtained for 316L SS specimens produced by Selective Laser Melting, when compared to Hot Pressing and conventional casting. The high wear and mechanical performance of 316L Stainless Steel fabricated by Selective Laser Melting are mainly due to the finer microstructure, induced by the process. In this sense, Selective Laser Melting seems a promising method to fabricate customized 316L SS implants with improved mechanical and wear performance
- Multi-material Ti6Al4V & PEEK cellular structures produced by Selective Laser Melting and Hot Pressing: A tribocorrosion study targeting orthopedic applicationsPublication . Bartolomeu, F.; Buciumeanu, M.; Costa, M.M.; Alves, N.; Gasik, M.; Silva, F.S.; Miranda, G.Ti6Al4V-alloy is commonly used in dental and orthopedic applications where tribochemical reactions occur at material/bone interface. These reactions are one of the main concerns regarding Ti6Al4V implants due to the generation of wear particles, linked to the release of metallic ions in toxic concentration which occurs when TiO2 passive film is destroyed by means of wear and corrosion simultaneously. In the present study, a multi-material Ti6Al4V-PEEK cellular structure is proposed. Selective Laser Melting technique was used to produce Ti6Al4V dense and cellular structured specimens, whilst Hot-Pressing technique was employed to obtain multi-material Ti6Al4V-PEEK structures. This study investigates the tribocorrosion behavior of these materials under reciprocating sliding, comparing them with commercial forged Ti6Al4V. Open-circuit-potential was measured before, during and after sliding while dynamic coefficient of friction was assessed during sliding. The results showed an improved wear resistance and a lower tendency to corrosion for the multi-material Ti6Al4V-PEEK specimens when compared to dense and cellular structures mono-material specimens. This multi-material solution gathering Ti6Al4V and PEEK, besides being able to withstand the loads occurring after implantation on dental and orthopedic applications, is a promising alternative to fully dense metals once it enhances the tribocorrosion performance.
- Ti6Al4V cellular structures impregnated with biomedical PEEK: New material design for improved tribological behaviorPublication . Buciumeanu, M.; Almeida, S.; Bartolomeu, F.; Costa, M.M.; Alves, N.; Silva, F.S.In the present work, a new material design of Ti6Al4V-PEEK hybrid cellular structure with improved wear resistance is proposed. Samples with different dimensions of the open-cells (350, 400, 450, 500 μm) were fabricated by Selective laser melting (SLM) technology, while Hot pressing (HP) technology was employed to produce Ti6Al4V-PEEK hybrid cellular structures. The tribological tests were performed in Phosphate Buffered Saline solution at 37 ± 2 C. Results demonstrated that the addition of the biomedical PEEK protected the Ti6Al4V cellular structures, thus improving these hybrid structures wear resistance when increasing the amount of PEEK. The obtained results indicated that the Ti6Al4V-PEEK hybrid cellular structure with the dimensions of the opencells of 500 μm is a suitable structure for orthopedic implants, with improved properties.