Effect of material stiffness on hardness: A computational study based on model potentials

Ziegenhain, Gerolf; Urbassek, Herbert M.

doi:10.1080/14786430903022697

Cited by 25 publications

(16 citation statements)

References 33 publications

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“…The simulations are performed at 0 K, since we are interested in the fundamental mechanisms of plasticity generation, and it is known that the thermal energy is not sufficient to initiate plasticity on the time scales of a molecular-dynamics simulation. 16 Islands are characterized by the number of rings S of adatoms around the island core, which are needed for their construction, cf. Figure 1.…”

Section: Systemmentioning

confidence: 99%

Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

Ziegenhain

Urbassek

2010

Phys. Rev. B

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Using molecular-dynamics simulation we investigate nanoindentation into an fcc metal surface covered by an adatom island. Small islands are pushed into the solid and transported away by prismatic dislocation loops, and no defects remain under the indenter; thereafter indentation proceeds as for a flat surface. For large islands, the island boundaries do not influence indentation. Most interesting is the intermediate case, where the island size is comparable to the contact radius of the indenter at the onset of plasticity. Here plasticity starts immediately at the surface under the weakest step edges bounding the island. The dislocations are pinned to the step edges and dislocation activity remains localized under the island. For this intermediate case, the surface is weakest and yields earliest.

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Section: Systemmentioning

confidence: 99%

Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

Ziegenhain

Urbassek

2010

Phys. Rev. B

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“…The indentation [1][2][3][4][5][6][7][8][9][10][11][12][13] and scratching [14][15][16][17][18][19][20][21][22][23][24] of surfaces has been intensely studied using molecular dynamics simulation. While the majority of these studies use rigid toolsin the sense that the indenter is undeformable and also non-rotating-also the effect of rotational motion has been investigated in several case studies [25][26][27][28][29][30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Indentation and Scratching with a Rotating Adhesive Tool: A Molecular Dynamics Simulation Study

Alhafez

Urbassek

2022

Tribol Lett

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For the specific case of a spherical diamond nanoparticle with 10 nm radius rolling over a planar Fe surface, we employ molecular dynamics simulation to study the processes of indentation and scratching. The particle is rotating (rolling). We focus on the influence of the adhesion force between the nanoparticle and the surface on the damage mechanisms on the surface; the adhesion is modeled by a pair potential with arbitrarily prescribed value of the adhesion strength. With increasing adhesion, the following effects are observed. The load needed for indentation decreases and so does the effective material hardness; this effect is considerably more pronounced than for a non-rotating particle. During scratching, the tangential force, and hence the friction coefficient, increase. The torque needed to keep the particle rolling adds to the total work for scratching; however, for a particle rolling without slip on the surface the total work is minimum. In this sense, a rolling particle induces the most efficient scratching process. For both indentation and scratching, the length of the dislocation network generated in the substrate reduces. After leaving the surface, the particle is (partially) covered with substrate atoms and the scratch groove is roughened. We demonstrate that these effects are based on substrate atom transport under the rotating particle from the front towards the rear; this transport already occurs for a repulsive particle but is severely intensified by adhesion.

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“…Some of these are: determination of residual stresses, defectoscopic methods, X-ray diffraction, methods based on photo-elasticimetry, etc. [14,15,16] Such a method is proposed in this paper, namely to establish a correlation between the degree of plastic deformation, suffered as a result of subjecting the part to different operating conditions and environment, and the size of Vickers hardness determined on those parts. This method is based on the fact that, after exceeding the elastic limit, the material hardens in its entire volume, thus changing its hardness.…”

Section: Introductionmentioning

confidence: 99%

Vickers Hardness Variation on the Part and Welding Cord Subjected to Plastic Deformation

Goanță

Moraras²

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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By performing Vickers identifications in the area of the weld bead and the areas adjacent to it, the degree of plastic deformation can be assessed, highlighting the different hardness in the case of welding and the base material. During this work, welded specimens were made in the central area with a double V-shaped cord. One of the specimens was loading until breaking, noting that the rupture occurred in an area further away from the welding area. Another 13 specimens were required at varying degrees of deformation. Stresses above the elastic limit create differences in the plastic deformation of the areas of the weld bead and those in its vicinity. Due to the fact that the base material and the material of the weld bead have different elastic characteristics, much more pronounced plastic deformations occur in the base material compared to the weld bead. It was found that the base material suffered significantly greater plastic deformation than the weld bead. Significant differences in hardness occur in the area of the weld bead relative to the area of the base material.

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Effect of material stiffness on hardness: A computational study based on model potentials

Cited by 25 publications

References 33 publications

Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

Indentation and Scratching with a Rotating Adhesive Tool: A Molecular Dynamics Simulation Study

Vickers Hardness Variation on the Part and Welding Cord Subjected to Plastic Deformation

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