Significantly improved mechanical and corrosion-resistant properties of NiTi alloy fabricated by selective laser melting through heat treatments

The poor processability of NiTi alloy is a major impediment in its practical applications in biomedical field. Selective laser melting (SLM) technology has been used to address this issue, but it introduces some defects such as pores and cracks into NiTi alloy, potentially hindering its suitability for biomedical implants. To mitigate this, the present study investigated the efficacy of solution treatment (ST) and hot isostatic pressure (HIP) on SLM NiTi alloy, with the aim of reducing defects and improving mechanical properties and corrosion resistance. Our results demonstrated that ST improved the aforementioned properties of NiTi alloy by reducing the defect size, while HIP almost eliminated the internal defects exhibiting the most favorable properties. These findings provide valuable insights into the optimization of SLM NiTi alloy for biomedical applications.