Investigation of effective coating of the Ti–6Al–4V alloy and 316L stainless steel with graphene or carbon nanotubes with finite element methods

Abstract

BackgroundThe Ti–6Al–4V alloy and 316L stainless steel are widely used biocompatible implant materials for repairing bone fractures and their mechanical properties are now being considered for various other applications. Due to the mentioned reasons, we initially investigated and determined the mechanical effects of these biocompatible implant materials. In the sequel, as a novelty of this study, we adopted a unique approach to investigating these materials and sought to determine if coating the Ti–6Al–4V alloy and 316L stainless steel with graphene or carbon nanotubes (CNTs) could provide superior mechanical properties compared to when their surface is uncoated. MethodsTo investigate the mechanical effects of the Ti–6Al–4V alloy and 316L stainless, finite element method was utilized. Finite element analyses (FEAs) of the Ti–6Al–4V alloy and 316L stainless steel samples were comparatively conducted with the numerical results in literature. Static structural analyses were generated for the externally fixated femur in the single-leg stance position. Comparative static load analyses were performed for six distinctive cases of the uncoated Ti–6Al–4V alloy and 316L stainless steel, and graphene-coated Ti–6Al–4V alloy, CNT-coated Ti–6Al–4V alloy, graphene-coated 316L stainless steel, and CNT-coated 316L stainless steel. ResultsThe results of the static load analyses of the six distinctive cases show that the uncoated Ti–6Al–4V, graphene-coated Ti–6Al–4V, and CNT-coated Ti–6Al–4V samples stress values are 48.29 MPa, 36.24 MPa, and 87.574 MPa for the femur, the first screw, and plate stresses, respectively. These stresses are the minimum stress values occurred on the femur, the first screw, and the plate, respectively. On the other hand, the graphene-coated 316L and CNT-coated 316L stainless steel samples had the minimum displacement values, which were obtained as 1.558 mm, 1.5576 mm at the femoral head, and 0.13029 mm, 0.13028 mm at the fracture line, respectively. ConclusionThe main result and conclusion of this study is that coating the Ti–6Al–4V alloy and 316L stainless steel samples with graphene or CNTs results in superior mechanical performance in comparison to when they are uncoated. Considering the FEAs of the six different materials, CNT- or graphene-coated Ti–6Al–4V and CNT- or graphene-coated 316L stainless steel are the most recommended finite element models (FEMs) in terms of stress and displacement values, respectively. By using CNT- or graphene-coated Ti–6Al–4V and CNT- or graphene-coated 316L stainless steel, more durable, stable externally fixated implants can be obtained for femoral shaft fractures in terms of stress and displacement reduction occurred on both femur and implants.