scholarly journals Mechanical properties of silicon in subsurface damage layer from nano-grinding studied by atomistic simulation

AIP Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 055223 ◽  
Author(s):  
Zhiwei Zhang ◽  
Pei Chen ◽  
Fei Qin ◽  
Tong An ◽  
Huiping Yu
Keyword(s):  
Mechanical Properties ◽  
Atomistic Simulation ◽  
Subsurface Damage ◽  
Damage Layer

Double-sided and single-sided polished 6H-SiC wafers with subsurface damage layer studied by Mueller matrix ellipsometry

2020 ◽  
Vol 128 (23) ◽  
pp. 235304
Author(s):  
Huihui Li ◽  
Changcai Cui ◽  
Subiao Bian ◽  
Jing Lu ◽  
Xipeng Xu ◽  
...  
Keyword(s):  
Mueller Matrix ◽  
Subsurface Damage ◽  
Damage Layer

scholarly journals Nondestructive Evaluation of Functionally Graded Subsurface Damage on Cylinders in Nuclear Installations Based on Circumferential SH Waves

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Zhen Qu ◽  
Xiaoqin Shen ◽  
Xiaoshan Cao
Keyword(s):  
Mechanical Properties ◽  
Phase Velocity ◽  
Nondestructive Evaluation ◽  
Surface Damage ◽  
Subsurface Damage ◽  
Functionally Graded ◽  
Horizontal Shear ◽  
Steel Cylinder ◽  
Sh Waves ◽  
Subsurface Layers

Subsurface damage could affect the service life of structures. In nuclear engineering, nondestructive evaluation and detection of the evaluation of the subsurface damage region are of great importance to ensure the safety of nuclear installations. In this paper, we propose the use of circumferential horizontal shear (SH) waves to detect mechanical properties of subsurface regions of damage on cylindrical structures. The regions of surface damage are considered to be functionally graded material (FGM) and the cylinder is considered to be a layered structure. The Bessel functions and the power series technique are employed to solve the governing equations. By analyzing the SH waves in the 12Cr-ODS ferritic steel cylinder, which is frequently applied in the nuclear installations, we discuss the relationship between the phase velocities of SH waves in the cylinder with subsurface layers of damage and the mechanical properties of the subsurface damaged regions. The results show that the subsurface damage could lead to decrease of the SH waves’ phase velocity. The gradient parameters, which represent the degree of subsurface damage, can be evaluated by the variation of the SH waves’ phase velocity. Research results of this study can provide theoretical guidance in nondestructive evaluation for use in the analysis of the reliability and durability of nuclear installations.

Length Scale Effects in Materials Deformation of Nano and Microscale Au Structures

2009 ◽  
Author(s):  
Jie Lian ◽  
Junlan Wang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Size Effect ◽  
Sample Size ◽  
Atomistic Simulation ◽  
Scale Effects ◽  
Elastic Recovery ◽  
Boundary Effect ◽  
Dislocation Nucleation ◽  
Atomistic Simulations

In this study, intrinsic size effect — strong size dependence of mechanical properties — in materials deformation was investigated by performing atomistic simulation of compression on Au (114) pyramids. Sample boundary effect — inaccurate measurement of mechanical properties when sample size is comparable to the indent size — in nanoindentation was also investigated by performing experiments and atomistic simulations of nanoindentation into nano- and micro-scale Au pillars and bulk Au (001) surfaces. For intrinsic size effect, dislocation nucleation and motions that contribute to size effect were analyzed for studying the materials deformation mechanisms. For sample boundary effect, in both experiments and atomistic simulation, the elastic modulus decreases with increasing indent size over sample size ratio. Significantly different dislocation motions contribute to the lower value of the elastic modulus measured in the pillar indentation. The presence of the free surface would allow the dislocations to annihilate, causing a higher elastic recovery during the unloading of pillar indentation.

scholarly journals Laser-assisted grinding of reaction-bonded SiC

2020 ◽  
Vol 3 (2) ◽  
pp. 93-98
Author(s):  
Xichun Luo ◽  
Zhipeng Li ◽  
Wenlong Chang ◽  
Yukui Cai ◽  
Jining Sun ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Process Development ◽  
Thermal Control ◽  
Subsurface Damage ◽  
Experimental Comparison ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Control Approach ◽  
Damage Layer ◽  
Conventional Grinding

The article presents the development of a novel laser-assisted grinding (LAG) process to reduce surface roughness and subsurface damage in grinding reaction-bonded silicon carbide (RB-SiC). A thermal control approach is proposed to facilitate the process development, in which a two-temperature model (TTM) is applied to control the required laser power to thermal softening of RB-SiC prior to the grinding operation without melting the workpiece or leaving undesirable microstructural alteration. Fourier’s law is adopted to obtain the thermal gradient for verification. An experimental comparison of conventional grinding and LAG shows significant reduction of machined surface roughness (37%–40%) and depth of subsurface damage layer (22%–50.6%) using the thermal control approach under the same grinding conditions. It also shows high specific grinding energy 1.5 times that in conventional grinding at the same depth of cut, which accounts for the reduction of subsurface damage as it provides enough energy to promote ductile-regime material removal.

Experimental Study on the Subsurface Damage in the Ultrasonic Vibration Grinding of Nano-ZrO2 Ceramics

2010 ◽  
Vol 42 ◽  
pp. 143-146 ◽  
Author(s):  
Ming Li Zhao ◽  
Bo Zhao ◽  
Yu Qing Wang ◽  
Ling Zhi Kong
Keyword(s):  
Ultrasonic Vibration ◽  
Vibration Mode ◽  
Longitudinal Vibration ◽  
Subsurface Damage ◽  
Bending Vibration ◽  
Effect Factor ◽  
Damage Layer ◽  
Grinding Method ◽  
Ultrasonic Grinding ◽  
Longitudinal Vibration Mode

Because of the hard-brittle character of ceramics, the ultrasonic vibration grinding method was used in the experiment. And the effects of ultrasonic vibration on the subsurface damage were analyzed in this paper. The experiment indicates that the frequency of 35 KHz will be more suitable for ultrasonic grinding ceramics, and under this frequency the damage layer thickness will be controlled in 11μm. The effect of vibration amplitude on the subsurface damage was also analyzed in this paper. The experiment results show that smaller amplitude will impair the efficiency of ultrasonic vibration grinding. The ultrasonic vibration mode was also an effect factor to the subsurface damage. Only the longitudinal vibration mode can improve the subsurface quality, while the bending vibration and torsion vibration will lead to the contrary results.

Research on the Distribution of Subsurface Damage Layer on SiC Substrate After Double-Side Lapping

2015 ◽  
Vol 14 (01) ◽  
pp. 1-10 ◽  
Author(s):  
Hai Zhou ◽  
Xiaoming Xu ◽  
Xiang Gao ◽  
Yuan Zhang
Keyword(s):  
Silicon Carbide ◽  
Surface Damage ◽  
Damage Mechanism ◽  
Processing Parameters ◽  
Subsurface Damage ◽  
Shape Measurement ◽  
Theoretic Model ◽  
Damage Layer ◽  
Silicon Carbide Substrate ◽  
Measurement Laser

In this paper, the surface damage mechanism of silicon carbide lapping process was studied. A theoretic model between the depth of subsurface damage and surface scratch of silicon carbide substrate double-side lapping has been built. An experiment of two-sided lapping combining VK-X100/X200 shape measurement laser microscopy system with HF mild chemical etching experiment on SiC substrate was processed to obtain the distribution of surface scratch and subsurface damage layer with depth. The study shows that the thickness of subsurface damage layer decreases as the depth increases, which centrally distributes in the depth of 0–15.6 μm from outer fragmentation and scratch damage layer, which accounted for about 98.6%. The result can help us to optimize processing parameters of silicon carbide substrate double-side lapping to control the depth of subsurface damage layer.

Study of mechanical properties and subsurface damage of quartz glass at high temperature based on MD simulation

2019 ◽  
Vol 04 (02) ◽  
pp. 1950003 ◽  
Author(s):  
Xiaoguang Guo ◽  
Chong Chen ◽  
Renke Kang ◽  
Zhuji Jin
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
High Temperature ◽  
Quartz Glass ◽  
Subsurface Damage ◽  
Simulation Based ◽  
Glass Model ◽  
Crystal Model ◽  
Higher Temperature ◽  
Lower Temperature

The mechanical properties (hardness, elastic modulus) and subsurface damage of quartz glass at high temperature are studied by nanoindentation simulation based on molecular dynamics (MD). By heating the quartz crystal model to 3000[Formula: see text]K and annealing to 300[Formula: see text]K twice, the quartz glass model is prepared. According to the nanoindentation simulation results, the hardness of quartz glass decreases by 53.6% and the elastic modulus increases by 10.9% at 1500[Formula: see text]K compared to those at 300[Formula: see text]K. When the temperature rises from 300[Formula: see text]K to 1500[Formula: see text]K, the critical grinding depth of quartz glass increases from nanoscale to micron-scale. The investigation of subsurface damage shows that the damaged layer thickness decreases slightly with the increase of temperature. The damaged layer extends downward under the indenter at lower temperature and extends along the indenter at higher temperature.

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