TY - JOUR
T1 - Elastic stress field model and micro-crack evolution for isotropic brittle materials during single grit scratching
AU - Wang, Wei
AU - Yao, Peng
AU - Wang, Jun
AU - Huang, Chuanzhen
AU - Kuriyagawa, Tsunemoto
AU - Zhu, Hongtao
AU - Zou, Bin
AU - Liu, Hanlian
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China (51305237), the Key Laboratory for Precision & Non-traditional Machining of Ministry of Education, Dalian University of Technology (JMTZ201504) and Key Laboratory of Optical System Advanced Manufacturing Technology (Y4GX1SJ141).
Publisher Copyright:
© 2017
PY - 2017/10/1
Y1 - 2017/10/1
N2 - An analytical model for the elastic stress field in isotropic hard and brittle materials during scratching is presented. The model considers the entire elastic stress field and the effect of material densification that was ignored in past studies, and is developed under a cylindrical coordinate system to make the modeling process simpler. Based on the model's predictions, the location and sequence of crack nucleation are estimated and the associated mechanisms are discussed. A single grit scratching experiment with an increasing scratch depth up to 2 µm is conducted for two types of optical glasses representing isotropic brittle materials: fused silica and BK7 glasses. It is found that the model's predictions correlate well with experimental data. Median cracks are found to be formed first during scratching, and the corresponding depth of the scratch sets the basis for determining the critical depth for brittle to ductile machining. Lateral cracks are initiated in the plastic yielding region and deflect to the work surface to cause material removal, while Hertzian cracks interact with lateral cracks to help remove lateral-cracked material. Furthermore, it is found that, owing to its open network molecular structure, fused silica has a much worse ductile machinability than the BK7 glass.
AB - An analytical model for the elastic stress field in isotropic hard and brittle materials during scratching is presented. The model considers the entire elastic stress field and the effect of material densification that was ignored in past studies, and is developed under a cylindrical coordinate system to make the modeling process simpler. Based on the model's predictions, the location and sequence of crack nucleation are estimated and the associated mechanisms are discussed. A single grit scratching experiment with an increasing scratch depth up to 2 µm is conducted for two types of optical glasses representing isotropic brittle materials: fused silica and BK7 glasses. It is found that the model's predictions correlate well with experimental data. Median cracks are found to be formed first during scratching, and the corresponding depth of the scratch sets the basis for determining the critical depth for brittle to ductile machining. Lateral cracks are initiated in the plastic yielding region and deflect to the work surface to cause material removal, while Hertzian cracks interact with lateral cracks to help remove lateral-cracked material. Furthermore, it is found that, owing to its open network molecular structure, fused silica has a much worse ductile machinability than the BK7 glass.
KW - Ductile to brittle transition
KW - Elastic stress field
KW - Isotropic brittle materials
KW - Micro-crack evolution
KW - Optical glass
KW - Single grit scratching
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U2 - 10.1016/j.ceramint.2017.05.054
DO - 10.1016/j.ceramint.2017.05.054
M3 - Article
AN - SCOPUS:85020409016
VL - 43
SP - 10726
EP - 10736
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 14
ER -