Evaluation of chemical composition, heat treatment, mechanical properties and electro chemical polishing for additively manufactured stent using ASTM F75 cobalt based superalloy (CoCrMo) by selective laser melting (SLM) technology.

This paper evaluates and demonstrates the methods for additively manufactured stent and the use of material ASTM F75 Cobalt-based superalloy (CoCrMo) by evaluating the chemical content, hot isostatic pressing process, mechanical properties, and electrochemical polishing. The commercialise stent available had cause issues in the like of unmatch fitting in the blood vessel, with highly dependent on surgeon guessing during angioplasty; thus, the risk of restenosis or thrombosis can occur. By SLM technique, it creates complex products with high geometric accuracy while allowing the design freedom to produce patient-specific stent. The heat treatment for additively manufactured stent has been done through a series of Hot Isostatic Pressing (HIPing) cycle 1200°C and 14,150 PSI. The sample preparation by chemical etching method was delivered to assess the effect of as-built sample and HIPing where it showed the change pattern of the microstructure. The chemical composition has been assessed by Energy-Dispersive X-ray spectroscopy (EDX) and showed the presence of element Cobalt, Chromium, Molybdenum, and Carbon content. The compressive, flexural, and hardness testing has been conducted to determine the behaviour for an as-built sample and HIPing where the stiffness is drastically improved by 10%. [ABSTRACT FROM AUTHOR]