A Novel Simulation Model for Multiple Solid Particle Erosion in Micro-blasting Process of Ti-6Al-4V Dental Implant Alloy Considering Actual Geometry of Impacting Particles

Dental implants undergo a general surface treatment via micro-blasting, where solid particle erosion (SPE) occurs on their surfaces. Considering the high costs of SPE experiments, it is necessary to present a reliable computer simulation that can provide a correct understanding of the erosion rate, residual stress and the characteristics of the scar created. However, simulating the impacts of numerous erosive particles with different shapes is challenging. This article, using numerical and experimental approaches, focused on effects of particle velocity and angle of impact on the surface responses of Ti-6Al-4V. In the simulation, the real shapes of more than 1500 angular particles were reproduced through an image processing technique. Johnson-Cook/Zerilli-Armstrong constitutive model was established for analysis. The accuracy of finite element (FE) and smoothed-particle hydrodynamics (SPH) was compared with experiments at oblique and normal micro-blasting in three velocities. Erosion rate, residual stress and scar area were investigated. Higher velocities showed more accurate erosion rate results with SPH, whereas the FE model suited lower ones. SPH outperformed FE in predicting surface residual stress. For normal impacts, the SPH was more reliable in predicting the scar area, while the FE was more accurate for oblique impacts. SEM results indicated both penetration and cutting mechanisms at 35°, but only pure penetration was the main mechanism at 90°.