Anisotropic Analysis on Processed Surface of KDP Single Crystals

2009 ◽  
Vol 76-78 ◽  
pp. 223-228 ◽  
Author(s):  
Chun Peng Lu ◽  
Hang Gao ◽  
Ben Wang ◽  
Qiang Guo Wang ◽  
Xiao Ji Teng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Slip System ◽  
Surface Quality ◽  
Potassium Dihydrogen Phosphate ◽  
Physical And Mechanical Properties ◽  
Surface Damage ◽  
Dihydrogen Phosphate ◽  
Strong Anisotropy ◽  
Machined Surface ◽  
Kdp Crystals

Strong anisotropy of physical and mechanical properties of Potassium Dihydrogen Phosphate (KDP) crystals significantly affects surface quality during processing the samples. Different processing direction, along [100], [110], and [120] crystallographic orientations, are chosen on (001) crystal plane in order to evaluate the anisotropic characterizations on the processed surface. Scanning electronic microscopy (SEM) is employed to observe the machined surface damage, defects and profiles. At the same time, surface quality is measured by Zygo surface profiler to estimate the processed surface quality. The results show that the machined surfaces along three different orientations under the same processing conditions behave quite differently from each other. Strong anisotropy and complex slip system of KDP crystals lead to several different asymmetric damages on the machined surface. Surface roughness (Ra) values along [100] are the smallest, that along [120] are in average, and that along [110] are largest. Moreover, many illustrations are given to understand the anisotropic nature during processing, including slip system, mechanical properties during processing, and technical parameters, etc.

Elastic-Plastic Deformation of KDP Crystals under Nanoindentation

2013 ◽  
Vol 773-774 ◽  
pp. 705-711 ◽  
Author(s):  
Jing Peng ◽  
Liang Chi Zhang ◽  
Xin Chun Lu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Potassium Dihydrogen Phosphate ◽  
Dislocation Nucleation ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Diamond Indenter ◽  
The Common ◽  
Kdp Crystals ◽  
Yielding Point

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after the first pop-in, the common method of obtaining elastic modulus from the unloading curve of nanoindentation is no longer applicable, because the unloading is inelastic.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.

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

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Creep Deformation ◽  
Potassium Dihydrogen Phosphate ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Machining Process ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

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.

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

2020 ◽  
Vol 8 (4) ◽  
pp. 447-456
Author(s):  
Yong Zhang ◽  
Ning Hou ◽  
Liang-Chi Zhang ◽  
Qi Wang
Keyword(s):  
Plastic Deformation ◽  
Brittle Fracture ◽  
Optical Switching ◽  
Potassium Dihydrogen Phosphate ◽  
Machining Process ◽  
Fracture Mechanisms ◽  
Dihydrogen Phosphate ◽  
Kdp Crystal ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

AbstractPotassium 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.

Kinetics of Potassium Dihydrogen Phosphate Single-Crystal Growth Mapped by the Chemical Bond Simulation

2012 ◽  
Vol 554-556 ◽  
pp. 31-34 ◽  
Author(s):  
Xu Zhang ◽  
De Xiang Jia
Keyword(s):  
Chemical Bond ◽  
Crystal Morphology ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Chemical Bonds ◽  
Potassium Dihydrogen ◽  
Solution Interface ◽  
Shape Controlled ◽  
Kinetics Of ◽  
Kdp Crystals

A chemical bond simulation was proposed to quantitatively calculate the growth rate from the kinetic model of the crystal-solution interface. When this approach was applied to the cases of potassium dihydrogen phosphate (KDP) crystals grown from the solution with different surpersaturation, the growth behaviors of KDP crystals were predicted and the calculated results were consistent with the experimental data. These results demonstrate that regulating the distribution of the chemical bonds between the crystal and solution interfaces can effectively control the crystal morphology. Seeding experiments with the chemical bond simulation may have significant potential towards the development of shape-controlled growth with defined conditions.

Studies of Potassium Dihydrogen Phosphate (KDP) Crystals Doped with Potassium Dichromate (PD) using ICP and UV Spectrophotometer

2007 ◽  
Vol 1015 ◽  
Author(s):  
Selemani Seif ◽  
Ravindra Behari Lal
Keyword(s):  
Potassium Dichromate ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
High Concentration ◽  
Potassium Dihydrogen ◽  
Evaporation Technique ◽  
Uv Transmittance ◽  
Kdp Crystals ◽  
Specific Amount

AbstractThis paper reports on preparation and characterization of Potassium Dihydrogen Phosphate (KDP) crystals doped with Potassium Dichromate (PD). The crystals were grown at room temperature by solution evaporation technique. The grown crystals were polished, sliced, and analyzed using UV-Spectrophotometer, which showed high concentration of PD impurities in KDP crystals at 200-280 nanometer. These concentrations were then verified using ICP measurements to determine specific amount in ppm of chromium ions in KDP crystals. In additional to that, the UV-transmittance data of these crystals were then converted to absorbance per thickness, and used to calculate absorption coefficients, extinction coefficients, and refractive index as a function of wavelength. The results showed that the presence of PD impurities in the crystal matrix of KDP has played a key reformative role in the UV sensing of Potassium Diphosphate crystals.

A Vacuum Sucking Approach to Preventing Chips from Attaching to Machined Surface in Cutting of KDP Crystals

2010 ◽  
Vol 443 ◽  
pp. 573-581
Author(s):  
Zi Wen Zheng ◽  
Hao Feng Chen ◽  
Yi Fan Dai ◽  
Hang Gao ◽  
Gui Lin Wang ◽  
...  
Keyword(s):  
High Power ◽  
Inertial Confinement Fusion ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Dihydrogen Phosphate ◽  
Inertial Confinement ◽  
Machined Surface ◽  
Kdp Crystals

Potassium Dihydrogen Phosphate (KDP) crystals are used for the key components in high power density solid-state laser for Inertial Confinement Fusion. KDP crystals are mainly machined in the dry cutting condition to avoid ‘Fogging’ of the crystals. The main difficulty identified in dry machining of KDP is chip removal from the machined surface. A vacuum sucking device based on venturi vacuum pump is used to suck the chips during cutting, and the relationship between level of vacuum in cutting zone and the comply air pressure was established. An empirical model for chip emission during turning processes is used to analyze the influence of cutting parameters on the chip emission. The influence of cutting parameters on the removal of chips is investigated. Finally, a face turning of KDP crystals is carried out with the turning parameters of feed rate 1um/rev, depth of cut of 0.8 um/rev and the cutting speed from 1.82m/s to 3.9m/s. A super-smooth surface with chips free in the whole sample is achieved, having the surface roughness of 2.994nm (Ra) measured by AFM. The surface quality achieved satisfies the requirements of KDP crystals implemented in high power lasers.

scholarly journals The effect of changing injection temperature on some mechanical and morphological properties for polypropylene material (PP)

2019 ◽  
Vol 24 (24) ◽  
pp. 20-24
Author(s):  
Ali Al-Zubiedy ◽  
Ruaa M. Muneer
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Injection Molding ◽  
Physical And Mechanical Properties ◽  
Surface Damage ◽  
Morphological Properties ◽  
Sem Images ◽  
Molding Temperature ◽  
Operation Temperature ◽  
Injection Temperature

Abstract This is a study of a medical injection factory-Babylon carried out in order to achieve proper mechanical and morphological properties, PP has been injection molded by using cold runner injection molding machine with temperature variation (198, 200, 203……220°C) for ten samples. The physical and mechanical properties of PP product were examined. It has been found that the Shore hardness decreases linearly with injection molding temperature increasing. The tensile strength has a similar behavior to the hardness. However, it has been found that the MIF (Melt Index Flow) rates increases with the increase of injection molding temperature. The density of PP has been found for both virgin PP and the samples, it has been found that the density decreases with increasing operation temperature. FTIR (Fourier Transmission Infrared) spectra were taken for both samples with high and low operation temperature. Besides the SEM (Scanning Electronic Microscopy) test shows the difference in the morphology of the product surface and the PP product at high and low operation temperature. Moreover, for all these properties, the PP product exhibits good mechanical properties (hardness, tensile strength, density) for the samples produced at temperature lower than 207°C. While the physical properties such as MIF improved with injection temperature increasing, additionally, the SEM images show that the sample produced in low temperature have surface damage.

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