TITLE:
Failure Analysis of Austenitic Stainless Steel Implant Screws and Prospection of Chemical Composition Using Artificial Intelligence
AUTHORS:
Alfonso Monzamodeth Román-Sedano, Bernardo Campillo, Fermín Castillo, Osvaldo Flores
KEYWORDS:
Implant Screw, Failure Analysis, Genetic Algorithm, Artificial Neural Network, Austenitic Stainless Steel
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.10 No.1,
February
25,
2022
ABSTRACT: In this work, austenitic stainless steel screws employed in a locking compression plate for veterinarian use were investigated. These types of implants are widely utilized in bone fractures healing. Two surgical screws were extracted due to the observation of slight superficial red rust colorizing on one of the screw implants, visual evidence of probable screw rusting. From the same implant, another screw was extracted simultaneously without visual evidence of rusting. In order to characterize and analyze the different behavior of bothscrews, the chemical composition was characterized by atomic absorption and energy dispersive X-ray spectroscopy (EDS) coupled to a scanning electronmicroscope (SEM). Also, the screws were studied by metallography, optical microscopy (OM), Vickers microhardness tests, and SEM analysis. On the otherhand, a prospection for alloy chemical composition limits of these types ofimplants was performed based on the Schaeffler-Delong diagram and the ASTM F-138 standard. To analyze the effect of the chemical composition,heat treatment, microstructure, pitting resistance equivalent number (PRE) and stacking fault energy (SFE), a genetic algorithm (GA) and an artificial neuralnetwork (ANN) were used. In accordance with the elemental analysis, thesurgical screws do not fulfill the ranges of the chemical composition established by the ASTM F-138 standard. Furthermore, there were found differencesbetween the microstructures of the screws. In regard to the prospection, the results of GA and ANN support the proposed chemical composition region on the Schaeffler-Delong diagram. The corrosion failure was associated with severe plastic deformation and the presence of precipitates. The proposal can minimize the cause of failures in these types of austenitic stainless steel implants.