Investigation of pop-in events and indentation size effect on the (001) and (100) faces of KDP crystals by nanoindentation deformation

Borc, J.; Sangwal, K.; Притула, И. М.; Dolzhenkova, E. F.

doi:10.1016/j.msea.2017.09.069

Cited by 25 publications

(16 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It can be seen that the MD results agree well with the JKR theory, indicating that the MD models established in this study are reliable. The corresponding Young’s moduli when indenting on the (001) and (100) surfaces were 54 and 66 GPa, respectively, aligned with the experimentally measured …”

Section: Resultssupporting

confidence: 83%

Effect of Anisotropy of Potassium Dihydrogen Phosphate Crystals on Its Deformation Mechanisms Subjected to Nanoindentation

Yang

Zhang

2021

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Potassium dihydrogen phosphate (KDP) is an important nonlinear material due to its excellent physical and optical properties. However, it is also a difficult-to-machine material due to its complex anisotropic microstructure. To better understand the deformation mechanisms under external stresses, this paper aims to carry out systematic nanoindentation simulations using molecular dynamics (MD). To facilitate the structural characterization of KDP, a machine learning-based method was developed. The results showed that the subsurface damage is obviously anisotropic. On the (001) surface, both tetragonal and monoclinic phases appear simultaneously and part of the monoclinic phase transfers to the tetragonal phase. The generated phases close to the surface undergo amorphization and are squeezed out to form pile-ups. On the (100) surface, however, an orthorhombic phase emerges directly from the original structure rather than transforming through the monoclinic phase. No amorphization happens and no pile-ups appear in this case. The first “pop-in” in the load–displacement curve of nanoindentation signified the emergence of phase transformation under the combined hydrostatic and shear stresses. After unloading, the recovery of the deformed KDP is also anisotropic. The maximum recovery takes place when the indentation is on the (100) surface.

show abstract

Section: Resultssupporting

confidence: 83%

Effect of Anisotropy of Potassium Dihydrogen Phosphate Crystals on Its Deformation Mechanisms Subjected to Nanoindentation

Yang

Zhang

2021

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…To the best of the author’s knowledge, this is the first report on detecting SRS for KDP crystals. Only in a few reports have researchers paid attention to the loading rate effect on elastic-to-plastic transition, i.e., the first pop-in event for KDP crystals [ 11 ]. The strain rate-concerned hardness has never been studied in KDP hitherto.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, the incipient plastic deformation in brittle KDP has attracted scientific interest at a very shallow depth by nanoindentation. Borc et al studied elastic-to-plastic transition via pop-in events on the (001) and (100) faces of KDP crystals by Berkovich nanoindentation [ 11 ]. Zhang et al studied incipient plasticity from the first pop-in event on the mechanical-polishing-damaged surface and nondamaged surface of KDP crystals [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Mao

Liu

et al. 2021

Micromachines

View full text Add to dashboard Cite

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

show abstract

“…These findings suggest that plastic deformations in KDP crystals may be produced at a microscale or nanoscale. Pop-in events are also correlated with the plastic deformation of KDP crystals during nanoindentation [12,13]. Kucheyev et al [11] observed multiple pop-in events in the load-displacement curves of KDP crystals and showed that under the 1 000 lN peak force with a spherical indenter, the first pop-in events appeared at loads of 225 ± 52 and 566 ± 87 lN on the (100) and (001) planes, respectively.…”

Section: Introductionmentioning

confidence: 98%

Elastic-plastic-brittle transitions of potassium dihydrogen phosphate crystals: characterization by nanoindentation

et al. 2020

View full text Add to dashboard Cite

Potassium dihydrogen phosphate (KDP) crystals are widely used in laser ignition facilities as optical switching and frequency conversion components. These crystals are soft, brittle, and sensitive to external conditions (e.g., humidity, temperature, and applied stress). Hence, conventional characterization methods, such as transmission electron microscopy, cannot be used to study the mechanisms of material deformation. Nevertheless, understanding the mechanism of plastic-brittle transition in KDP crystals is important to prevent the fracture damage during the machining process. This study explores the plastic deformation and brittle fracture mechanisms of KDP crystals through nanoindentation experiments and theoretical calculations. The results show that dislocation nucleation and propagation are the main mechanisms of plastic deformation in KDP crystals, and dislocation pileup leads to brittle fracture during nanoindentation. Nanoindentation experiments using various indenters indicate that the external stress fields influence the plastic deformation of KDP crystals, and plastic deformation and brittle fracture are related to the material's anisotropy. However, the effect of loading rate on the KDP crystal deformation is practically negligible. The results of this research provide important information on reducing machining-induced damage and further improving the optical performance of KDP crystal components.

show abstract

Investigation of pop-in events and indentation size effect on the (001) and (100) faces of KDP crystals by nanoindentation deformation

Cited by 25 publications

References 36 publications

Effect of Anisotropy of Potassium Dihydrogen Phosphate Crystals on Its Deformation Mechanisms Subjected to Nanoindentation

Effect of Anisotropy of Potassium Dihydrogen Phosphate Crystals on Its Deformation Mechanisms Subjected to Nanoindentation

The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Elastic-plastic-brittle transitions of potassium dihydrogen phosphate crystals: characterization by nanoindentation

Contact Info

Product

Resources

About