Micro porosity analysis in additive manufactured NiTi parts using micro computed tomography and electron microscopy

Long-term fixation of biomedical implants is achievable by using porous materials. These kinds of materials can produce a stable bone-implant interface. A critical aspect in production of porous implants is the design of macro and micro pores. In this research, a micro direct metal deposition process, newly developed as a potential method for implant production, was used to fabricate porous NiTi parts. The effect of process parameters on formation and distribution of micro pores was analysed using micro computed tomography and scanning electron microscopy. The analysis showed that, by increasing the laser scanning speed, inherent micro porosity increases. Also, it was found that there is an optimum temperature to achieve minimum inherent micro porosity by micro direct metal deposition which is 300. °C for NiTi powder.