The Experts below are selected from a list of 4764 Experts worldwide ranked by ideXlab platform
Zhuo Wang - One of the best experts on this subject based on the ideXlab platform.
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relationship between subsurface damage and surface roughness of optical materials in grinding and lapping processes
Journal of Materials Processing Technology, 2008Co-Authors: Zhuo WangAbstract:Abstract Subsurface damage generated in manufacturing processes directly influences performances of optical elements, however, the rapid inspection of subsurface damage is unresolved for it is covered under surface. For the purpose of rapid, accurate, and non-destructive measurement of subsurface damage produced in optical grinding and lapping processes, a theoretical model of relationship between subsurface damage and surface roughness was established through investigating median and Lateral Crack system in brittle surface induced by sharp indenter, and contribution of elastic stress field to the median Crack propagation was also considered in the loading cycle. With this model, subsurface damage depth can be predicted accurately via measuring surface roughness of manufactured optical elements. The subsurface damage depth and surface roughness of ground and lapped BK7 glass were measured by MRF (magnetorheological finishing) spot technique and contacting profilometer, respectively, in order to verify the validity of the relationship model. The results show that the relationship model is convenient and accurate in predicting the subsurface damage depth. And there exists monotone increasing non-linear correlation between subsurface damage depth and surface roughness ( p − v value) in optical grinding and lapping processes. At last the relationship between subsurface damage depth and process conditions in grinding and lapping processes and material mechanical properties is discussed.
Q.s. Xia - One of the best experts on this subject based on the ideXlab platform.
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Adhesion energy and related plastic deformation mechanism of Cu/Ru nanostructured multilayer film
Journal of Alloys and Compounds, 2019Co-Authors: Qing Zhou, Yanyan Ren, Dongpeng Hua, Weichao Han, Q.s. XiaAbstract:Abstract Sputter-deposited Cu/Ru nanolaminate composites with individual layer thickness as small as 1.5 nm were tested by nanoindentation probing to initiate and drive delamination. Focused ion beam (FIB) observations show the layer buckling and interface delamination with Lateral Crack along the interface between the multilayer and substrate. The buckling behaviors, dependent on the critical length scale, are rationalized in the light of the repeating structural unit in the coherent multilayer. In addition, due to the presence of the interfaces and constraints between the hetero-layers, the condition for plastic dissipation in multilayers shifts significantly from those of single layer films, therefore a modified energy-dissipative model has been employed to obtain the quantitative adhesion energy for Cu/Ru multilayer, which agrees well with previous reports on the Cu-based films adherent on rigid substrates. The present result provides meaningful adhesion energy estimates and helps to understand the underlying deformation mechanism in metallic multilayers.
Qing Zhou - One of the best experts on this subject based on the ideXlab platform.
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Adhesion energy and related plastic deformation mechanism of Cu/Ru nanostructured multilayer film
Journal of Alloys and Compounds, 2019Co-Authors: Qing Zhou, Yanyan Ren, Dongpeng Hua, Weichao Han, Q.s. XiaAbstract:Abstract Sputter-deposited Cu/Ru nanolaminate composites with individual layer thickness as small as 1.5 nm were tested by nanoindentation probing to initiate and drive delamination. Focused ion beam (FIB) observations show the layer buckling and interface delamination with Lateral Crack along the interface between the multilayer and substrate. The buckling behaviors, dependent on the critical length scale, are rationalized in the light of the repeating structural unit in the coherent multilayer. In addition, due to the presence of the interfaces and constraints between the hetero-layers, the condition for plastic dissipation in multilayers shifts significantly from those of single layer films, therefore a modified energy-dissipative model has been employed to obtain the quantitative adhesion energy for Cu/Ru multilayer, which agrees well with previous reports on the Cu-based films adherent on rigid substrates. The present result provides meaningful adhesion energy estimates and helps to understand the underlying deformation mechanism in metallic multilayers.
Xi Chen - One of the best experts on this subject based on the ideXlab platform.
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indentation induced Lateral Crack in ceramics with surface hardening
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Akio Yonezu, Xi ChenAbstract:Abstract Indentation is widely used to probe the fracture toughness of brittle materials such as ceramics or glass. In use, a hardened surface layer is inevitable in ceramics due to grinding and polishing; the surface layer also exists during sample preparation for indentation test. We study the mechanics of indentation induced Lateral Cracking in TiB 2 (titanium di-boride) ceramics, and show that the surface hardened layer has a pronounced effect on the initiation position of Lateral Crack, thereby affecting the wear resistance rate. The occurrence of Lateral Crack underneath the surface is detected in situ by an integrated acoustic emission (AE) and corrosion potential fluctuation (CPF) technique. By computing the detailed stress distribution, we discuss the mechanics of Lateral Crack formation in ceramics under the influence of surface hardening. It is found that when the maximum contact force is low, the Lateral Crack is confined within the surface layer, whereas when the maximum indentation force is high, the Crack prefers to nucleate at the interface. The findings in this paper may be useful to optimize the surface polishing process and improve wear properties of ceramics.
Dohyung Lee - One of the best experts on this subject based on the ideXlab platform.
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Lateral Crack in abrasive wear of brittle materials
Jsme International Journal Series A-solid Mechanics and Material Engineering, 2003Co-Authors: Yoomin Ahn, Nahmgyoo Cho, Seoung Hwan Lee, Dohyung LeeAbstract:An analytical model for Lateral Cracks occurring in abrasive wear of brittle materials was developed. The stress field around the Lateral Crack and the stress intensity factor at the Crack tip were analytically modeled. The abrasive wear by abrasive particles was experimentally studied by sliding indentation. In soda-lime glass, it was observed that chipping by the Lateral Crack occurred and produced the greatest material removal when the normal load applied by the sliding indenter was about 1.5-2.0N. Prediction of length of the Lateral Crack from the model was compared with the experimentally measured length in the soda-lime glass.
