arXiv subjects

G. C. Mondragón-Rodríguez

Publications and source records attributed to G. C. Mondragón-Rodríguez.

3 recordsLinked to original sources

arXiv2020

Effect of Self-Lubricating Carbon Materials on the Tribological Performance of Ultra-High-Molecular-Weight Polyethylene

Ultra-high-molecular-weight polyethylene (UHMWPE) has been the gold standard for total knee replacements. Due to the knee's natural movements, UHMWPE wear debris production is inevitable. The debris, at the micron and submicron level, results in the joint's mechanical instability, reduced mobility, increased pain, and implant loosening. Wear debris production has been linked to UHMWPE mechanical properties; therefore, improvements to increase the UHMWPE mechanical properties will impact the component's longevity. Here, TiC coating and multiwalled carbon nanotubes (MWCNTs) were used to decrease the UHMWPE wear. After 400,000 cycles, the UHMWPE-MWCNT diminishes the mass loss compared to UHMWPE, and the combination with TiC decreased the material loss by ~ 43.7 % compared to the reference pair. Cold-flow and burnishing were the predominant wear modes.

cond-mat.mtrl-sci↗

arXiv2018

Effect of Graded Bias Voltage on the Microstructure of arc-PVD CrN Films and its Response in Electrochemical & Mechanical Behavior

The effect of graded or constant bias voltages (-40 V, -80 V and -40/60/80 V) on size grain and surface defects of arc PVD deposited CrN films was investigated. Corrosion resistance evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic curves (Tafel) and the mechanical behavior evaluated by means of instrumented nanoindentation and scratch testing was correlated with the microstructural changes. It was found that the bias voltage variation affects corrosion behavior due to the presence of defects (i.e. open voids, droplets) which also affects the failure mechanisms and increasing spallation. High bias voltage (-80 V) increases nano-hardness and the elastic modulus due to the dense microstructure of the CrN coating.

physics.app-ph↗

arXiv2018

Theoretical-Experimental failure analysis of the c-Al0.66Ti0.33N-M2 steel system using nanoindentation instrumented and finite element analysis

A theoretical-experimental methodology for failure analysis of the c-Al0.66Ti0.33N / Interface / M2 steel coating system is proposed here. This c-Al0.66Ti0.33N coating was deposited by the arc-PVD technique. For coating modeling the traction-separation law and the extended finite element method-XFEM were applied, the cohesive zones model was used for interface modeling and the Ramberg-Osgood law for substrate modeling. Experimental values using the instrumented nanoindentation technique, the scratch test and tensile stress test were obtained and introduced into the model. By means of nanoindentation the elastic modulus of coating, the fracture energy release rate and the nano-hardness. Normal and shear stress values of the interface were obtained with the scratch test, at the adhesive and cohesive critical loads. Vickers indentation was used to generate cracking patterns in the c-Al0.66Ti0.33N / Interface / M2 steel coating system. Radial and lateral cracks were generated and analyzed after transversal FIB cuts of the fracture zones. A finite element analysis was carried out to understand the relationship between the load-displacement curve and mechanical failure of in the system, associating the pop-in with nucleation, crack growth and cracking pattern. This works present a theoretical-experimental methodology for failure analysis of hard coatings (monolithic body) allowing to calculate fracture toughness of the coating material and model cracking patterns caused by contact mechanics.

cond-mat.mtrl-sci↗