by Valencia, Felipe J., Santiago, José, González, Rafael I., González-Arrabal, Raquel, Ruestes, Carlos, Perez Díaz, Miguel, Monclus, Miguel A., Molina-Aldareguia, Jon, Nuñez, Pablo Diaz, Munoz, Francisco, Kiwi, Miguel, Perlado, Jose M. and Bringa, Eduardo M.
Abstract:
Amorphous carbon (aC), in particular diamond-like carbon (DLC), is one of the most studied and promising coating materials, but many of the atomic-scale mechanisms involved in their plastic deformation process are not fully understood. The mechanical response of non-hydrogenated DLC films with different sp3 concentrations is investigated using nanoindentation experiments, ab-initio simulations, and classical molecular dynamics simulations. Experimental characterization is carried out with Raman spectroscopy and Electron Energy Loss Spectroscopy (EELS). Ab-initio and classical simulations show good agreement for sp1, sp2 and sp3 content of in-silico samples. Elastic modulus and hardness of DLC films increase with sp3 content, for sp3 between 10% and 55%, and excellent agreement is obtained between experiments and simulations. Simulated strain distributions are shown to be highly anisotropic, unlike continuum-scale predictions for the use of a perfectly spherical indenter in an amorphous solid. MD simulations also reveal two different plasticity modes depending on the sp3 level of the indented sample. For films with sp3 concentrations less than 40%, plasticity is mainly mediated by the sp2 to sp3 transition. For larger sp3 concentrations, DLC plastic deformation is attributed to densification due to bond rearrangement. All in all, our work offers a comprehensive study of DLC, revealing unexpected plastic deformation mechanisms that had not been considered before. Our study might help to the fundamental understanding of amorphous carbon coatings for both scientific and technological purposes.
Reference:
Nanoindentation of Amorphous Carbon: a combined experimental and simulation approach. Valencia, Felipe J., Santiago, José, González, Rafael I., González-Arrabal, Raquel, Ruestes, Carlos, Perez Díaz, Miguel, Monclus, Miguel A., Molina-Aldareguia, Jon, Nuñez, Pablo Diaz, Munoz, Francisco, Kiwi, Miguel, Perlado, Jose M. and Bringa, Eduardo M., In Acta Materialia, 2020.
Bibtex Entry:
@article{valencia_nanoindentation_2020,
	title = {Nanoindentation of {Amorphous} {Carbon}: a combined experimental and simulation approach},
	issn = {1359-6454},
	shorttitle = {Nanoindentation of {Amorphous} {Carbon}},
	url = {http://www.sciencedirect.com/science/article/pii/S1359645420309022},
	doi = {10.1016/j.actamat.2020.116485},
	abstract = {Amorphous carbon (aC), in particular diamond-like carbon (DLC), is one of the most studied and promising coating materials, but many of the atomic-scale mechanisms involved in their plastic deformation process are not fully understood. The mechanical response of non-hydrogenated DLC films with different sp3 concentrations is investigated using nanoindentation experiments, ab-initio simulations, and classical molecular dynamics simulations. Experimental characterization is carried out with Raman spectroscopy and Electron Energy Loss Spectroscopy (EELS). Ab-initio and classical simulations show good agreement for sp1, sp2 and sp3 content of in-silico samples. Elastic modulus and hardness of DLC films increase with sp3 content, for sp3 between 10% and 55%, and excellent agreement is obtained between experiments and simulations. Simulated strain distributions are shown to be highly anisotropic, unlike continuum-scale predictions for the use of a perfectly spherical indenter in an amorphous solid. MD simulations also reveal two different plasticity modes depending on the sp3 level of the indented sample. For films with sp3 concentrations less than 40%, plasticity is mainly mediated by the sp2 to sp3 transition. For larger sp3 concentrations, DLC plastic deformation is attributed to densification due to bond rearrangement. All in all, our work offers a comprehensive study of DLC, revealing unexpected plastic deformation mechanisms that had not been considered before. Our study might help to the fundamental understanding of amorphous carbon coatings for both scientific and technological purposes.},
	language = {en},
	urldate = {2020-11-24},
	journal = {Acta Materialia},
	author = {Valencia, Felipe J. and Santiago, José and González, Rafael I. and González-Arrabal, Raquel and Ruestes, Carlos and Perez Díaz, Miguel and Monclus, Miguel A. and Molina-Aldareguia, Jon and Nuñez, Pablo Diaz and Munoz, Francisco and Kiwi, Miguel and Perlado, Jose M. and Bringa, Eduardo M.},
	month = nov,
	year = {2020},
	pages = {116485},
	file = {ScienceDirect Snapshot:C:\Users\Javier\Zotero\storage\78X68IB9\S1359645420309022.html:text/html}
}