Influence of dislocation density on the pop-in behavior and indentation size effect in CaF2 single crystals: Experiments and molecular dynamics simulations

Lodes, Matthias A.; Hartmaier, Alexander; Göken, Mathias; Durst, Karsten

doi:10.1016/j.actamat.2011.03.050

Cited by 120 publications

(89 citation statements)

References 43 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pop-in behavior has already been observed in tungsten [8,9]. The pop-in effect is believed to be caused by uniform nucleation and/or rapid multiplication (avalanche) of dislocations, leading to a sharp hardness drop and enhanced slip in the vicinity of the indented domain [10][11][12][13]. This interpretation is based on the observation that the resolved shear stress required to trigger a pop-in event is close to the theoretical strength of the material, / 2 G  , where G is the shear modulus [14].…”

Section: Introductionmentioning

confidence: 99%

“…This interpretation is based on the observation that the resolved shear stress required to trigger a pop-in event is close to the theoretical strength of the material, / 2 G  , where G is the shear modulus [14]. Furthermore, increasing the number of glissile dislocations leads to a decrease in pop-in load or even extinction of the pop-in effect [12]. The critical resolved shear stress needed for initiating a slip event can be estimated from the corresponding pop-in load.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of hydrogen on the slip resistance of tungsten single crystals

Yao

Wang

Manhard

et al. 2013

Materials Science and Engineering: A

View full text Add to dashboard Cite

The intense influx of hydrogen plasma onto the tungsten wall of a nuclear fusion reactor causes severe microstructural damage in the near-surface layer. The evolution of hydrogen-induced damage is often promoted by local plastic flow. Since hydrogen solutes are known to lower the hardness of many metals, the question arises as to the extent to which the tungsten walls are softened by the implantation of hydrogen. In this study, we investigated the change in slip resistance of tungsten single crystals following deuterium implantation. To determine the inherent yield stress of tungsten, we performed nanoindentation on high-purity single crystals. The statistical distribution of pop-in stresses (yield stress upon a single slip) revealed a significant reduction in pop-in load upon hydrogen implantation. In addition, the average stress at pop-in was found to be a function of crystallographic orientation of the samples, with much larger pop-in loads observed on (100) and (110) surface planes than on (111) surfaces.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of hydrogen on the slip resistance of tungsten single crystals

Yao

Wang

Manhard

et al. 2013

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…The size effect has been analysed in a series of papers by Durst et al [13][14][15], where the single crystal CaF 2 as well as nanocrystaline and single crystal metals were investigated.…”

Section: Introductionmentioning

confidence: 99%

Decrease of Nano-hardness at Ultra-low Indentation Depths in Copper Single Crystal

et al. 2015

View full text Add to dashboard Cite

In the present study, we report a detailed investigation of the unusual size effect in single crystals. For the experiments we specified the hardness in single crystalline copper specimens with different orientations ( (001), (011) and (111)) using Oliver-Pharr method. Our results indicates that with decreasing load, after the value of the hardness reached its maximum, it starts to decrease for very small indentation depths (<150 nm). For the sake of accuracy of hardness determination we have developed two AFM-based methods to evaluate contact area between tip and indented material. The proposed exact measurement of the contact area, which includes the effect of pile-up and sink-in patterns, can partially explain the strange behaviour, however, the decrease of hardness at low loads is still observed. At higher loads range the specified hardness is practically constant.

show abstract

“…In such instances, the indentation starts with an elastic loading that follows the Hertzian contact model. [100][101][102][103][104][105][106] As the shear stress below the tip in the volume of the material approaches the theoretical stress required for homogeneous dislocation nucleation, a sudden jump, i.e., the so-called pop-in, in the displacement occurs. The pop-in marks the transition from elastic to elastoplastic deformation in a perfect crystal.…”

Section: On the Trail Of Hydrogenmentioning

confidence: 99%

Materials and Corrosion Trends in Offshore and Subsea Oil and Gas Production

Iannuzzi¹,

Barnoush²,

Johnsen³

2017

Preprint

View full text Add to dashboard Cite

The ever-growing energy demand requires the exploration and the safe, profitable exploitation of unconventional reserves. The extreme environments of some of these unique prospects challenge the boundaries of traditional engineering alloys, as well as our understanding of the underlying degradation mechanisms that could lead to a failure. Despite their complexity, high-pressure and high-temperature, deep and ultra-deep, pre-salt, and Arctic reservoirs represent the most important source of innovation regarding materials technology, design methodologies, and corrosion control strategies. This paper provides an overview of trends in materials and corrosion research and development, with focus on subsea production but applicable to the entire industry. Emphasis is given to environmentally assisted cracking of high strength alloys and advanced characterization techniques based on in situ electrochemical nanoindentation and cantilever bending testing for the study of microstructure-environment interactions.

show abstract

Influence of dislocation density on the pop-in behavior and indentation size effect in CaF2 single crystals: Experiments and molecular dynamics simulations

Cited by 120 publications

References 43 publications

Effect of hydrogen on the slip resistance of tungsten single crystals

Effect of hydrogen on the slip resistance of tungsten single crystals

Decrease of Nano-hardness at Ultra-low Indentation Depths in Copper Single Crystal

Materials and Corrosion Trends in Offshore and Subsea Oil and Gas Production

Contact Info

Product

Resources

About