Revealing the mechanical properties of potassium dihydrogen phosphate crystals by nanoindentation

2016 ◽  
Vol 31 (8) ◽  
pp. 1056-1064 ◽  
Author(s):  
Y. Zhang ◽  
L.C. Zhang ◽  
M. Liu ◽  
F.H. Zhang ◽  
K. Mylvaganam ◽  
...  

Abstract

2013 ◽  
Vol 773-774 ◽  
pp. 705-711 ◽  
Author(s):  
Jing Peng ◽  
Liang Chi Zhang ◽  
Xin Chun Lu

This paper investigates the mechanical properties of potassium dihydrogen phosphate (KDP) crystals with the aid of nanoindentation using a conical diamond indenter. It was found that when unloading is after the first pop-in, the common method of obtaining elastic modulus from the unloading curve of nanoindentation is no longer applicable, because the unloading is inelastic. The study revealed that the pop-in could be due to dislocation nucleation and propagation, and that the first pop-in occurs under a stress below that of the major dislocation burst. Hence, the macroscopic yielding point, which is usually regarded as the onset of plasticity of a material, is nanoscopically not a critical point of the first dislocation in KDP. The study found that the elastic modulus of KDP indenting on its (001) plane is 52.8±3.8GPa. The hardness of the material is 1.89±0.05GPa.


1985 ◽  
Vol 40 (11) ◽  
pp. 1164-1166
Author(s):  
O. P. Agarwal ◽  
Prem Chand

Results of the optical absorption study of vanadyl ion doped in magnesium ammonium sulphate hexahydrate, rubidium sulphate and potassium dihydrogen phosphate single crystals at RT are reported. The nature of optical bands suggests a C4v symmetry of the Vanadyl complexes in conformity with the EPR results. Powder EPR data and optical data are correlated to obtain the MO coefficients.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma

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.


Author(s):  
A. Sivakumar ◽  
S. Sahaya Jude Dhas ◽  
P. Sivaprakash ◽  
Abdulrahman I. Almansour ◽  
Raju Suresh Kumar ◽  
...  

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