Changes of cytotoxicity of Ti-6Al-4V alloy made by DMLS technology as effect of the shot peening

Abstract

Objective. The aim the study was to investigate the impact of the shot peening process on the condition of the surface layer and biological properties of titanium alloy produced by means of the Direct Metal Laser Sintering (DMLS) method. Materials and method. Specimens were prepared by the EOSINT M280 metal sintering laser system. The surfaces were subjected to the shot peening process using three different media, i.e. steel shot, nutshell granules and ceramic beads, after which they were subjected to profilometric analysis, scanning electron microscopic (SEM) observations and energy dispersive X-ray spectroscopy (EDS) tests, as well as to assessment of biological compatibility in terms of cytotoxicity (SH-SY5Y cell lines). Results. The general results obtained from the tests indicate satisfactory biocompatibility of the examined surfaces and that the impact of the shot peening process on the titanium alloy cytotoxicity is acceptable. Conclusions. The lowest cytotoxicity was demonstrated by the surfaces modified by ceramic beads than the nutshells and the biggest steel shot correspondingly. Moreover, the shot peening process carried out by means of CrNi steel and ceramic shot caused the reduction of surface roughness when, for the surface processing by means of nutshell granules, the increase of surface roughness was observed compared with the unmodified surface of titanium alloy samples.

Effect of Shot Peening Parameters on Surface Properties and Corrosion Resistance of 316L Stainless Steel

“…Most of the research studies on metal treatment for medical purposes describe the use of high impact energy shot associated with the use of steel shot, as this translates mainly into favorable mechanical properties, while marginalizing the corrosion behavior [26]. And yet, the choice of pressing medium can have a key impact on the cytotoxicity and, consequently, biocompatibility of treated parts for medical purposes [27][28][29]. It seems that more favorable results in terms of corrosion resistance (which also translates into biocompatibility) can be obtained by shot peening using bioinert ceramics.…”