Crack Profile under Vickers Indents

2009 ◽  
Vol 409 ◽  
pp. 295-299
Author(s):  
Zdenĕk Jonšta ◽  
Lucie Olejníčková ◽  
Karel Mazanec
Keyword(s):  
Crack Formation ◽  
Cutting Tool ◽  
Ceramic Materials ◽  
Evaluation Methods ◽  
Technical Application ◽  
Lateral Crack ◽  
Complex Evaluation ◽  
Tool Ceramics ◽  
Physical Engineering ◽  
Crack Profile

The present work is focused on complex evaluation of crack profiles, created around Vickers indents in two types of cutting tool ceramics, namely in the Al2O3 + ZrO2 ceramics and -Si3N4. The geometry of Vickers indents is investigated using two different evaluation methods. The first one is based on the application of serial sectioning from the indented specimen surface. The second method consists in the layer removing from plane perpendicular to the indented surface. These evaluation methods are convenient for determine the shape of created cracks and profiles of deformed area developed around the investigated indents. The mentioned methods contribute to the understanding of physical engineering principles resulting from the radial/median and lateral crack formation as the important characteristics influencing the reliable technical application of investigated ceramic materials.

Forecasting Performance of Ceramic Cutting Tool

2017 ◽  
Vol 736 ◽  
pp. 86-90 ◽  
Author(s):  
Vyacheslav Maksarov ◽  
A. Khalimonenko
Keyword(s):  
Electrical Resistance ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Tool Material ◽  
Ceramic Materials ◽  
Specific Electrical Resistance ◽  
Testing Methods ◽  
Microstructural Parameters ◽  
Forecasting Performance ◽  
Nondestructive Testing Methods

The article considers the problems of forecasting the performance of cutting tools equipped with replaceable ceramic cutting bits. It is proposed to forecast the operability of ceramic tools on the ground of dependence between its performance characteristics and the microstructural parameters of the tool material. It is proposed to determine the parameters of ceramic bits microstructure by a nondestructive testing methods based on measuring the specific electrical resistance of ceramic materials. As a result of the study we have undertaken, a relationship was detected between the performance and specific electrical resistance of ceramic cutting tools.

Analysis of Pop-In Phenomenon in the Process of Ceramic Materials Instrumented Indentation

2014 ◽  
Vol 941-944 ◽  
pp. 564-568
Author(s):  
Jia Liang Wang ◽  
De Jun Ma ◽  
Wei Chen ◽  
Yong Huang ◽  
Liang Sun
Keyword(s):  
Radial Crack ◽  
Ceramic Materials ◽  
Mechanism Analysis ◽  
Analysis Method ◽  
Instrumented Indentation ◽  
Element Analysis ◽  
Lateral Crack ◽  
Indentation Process ◽  
The Finite Element Analysis ◽  
The Relationship

Based on the finite element analysis method, the relationship between two systems of crack (radial crack and lateral crack) and pop-in phenomenon were compared during the instrumented indentation process in ceramic materials. In order to give a reasonable explanation for mechanism analysis of pop-in phenomenon in the process of ceramic materials instrumented indentation, this paper proposed the viewpoint that pop-in phenomenon is caused by the lateral crack in the process of ceramic materials instrumented indentation. This work provided a theoretical basis for the study of instrumented indentation methodologies based on the pop-in phenomenon to determining mechanical properties of ceramic materials.

scholarly journals Nanoscale stacking fault–assisted room temperature plasticity in flash-sintered TiO2

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw5519 ◽  
Author(s):  
Jin Li ◽  
Jaehun Cho ◽  
Jie Ding ◽  
Harry Charalambous ◽  
Sichuang Xue ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Crack Formation ◽  
High Stress ◽  
Ceramic Materials ◽  
Sintering Process ◽  
Flash Sintering ◽  
Structural Applications ◽  
Deformation Behaviors

Ceramic materials have been widely used for structural applications. However, most ceramics have rather limited plasticity at low temperatures and fracture well before the onset of plastic yielding. The brittle nature of ceramics arises from the lack of dislocation activity and the need for high stress to nucleate dislocations. Here, we have investigated the deformability of TiO2 prepared by a flash-sintering technique. Our in situ studies show that the flash-sintered TiO2 can be compressed to ~10% strain under room temperature without noticeable crack formation. The room temperature plasticity in flash-sintered TiO2 is attributed to the formation of nanoscale stacking faults and nanotwins, which may be assisted by the high-density preexisting defects and oxygen vacancies introduced by the flash-sintering process. Distinct deformation behaviors have been observed in flash-sintered TiO2 deformed at different testing temperatures, ranging from room temperature to 600°C. Potential mechanisms that may render ductile ceramic materials are discussed.

Cutting Ceramic Materials: Influence of Abrasive Machining and Coating Deposition on the Performance Potential

2014 ◽  
Vol 1025-1026 ◽  
pp. 317-324 ◽  
Author(s):  
Sergey Nikolaevich Grigoriev ◽  
Marina Volosova ◽  
Yury Andreevich Melnik ◽  
Natalia Cherkasova ◽  
Alina Gurkina
Keyword(s):  
High Speed ◽  
Cutting Tool ◽  
Combined Treatment ◽  
Cutting Tools ◽  
Ceramic Materials ◽  
Abrasive Machining ◽  
Performance Potential ◽  
Vacuum Plasma ◽  
Operational Characteristics ◽  
Cutting Ceramic

Ceramic cutting tools have a large potential by high speed processing of difficult-to-cut steels and alloys, however due to its fragility they don’t assure the required reliability level of cutting process. For improving the operational characteristics of the ceramic cutting tool combined treatment can be used namely the preliminary planetary grinding of the insert surface and the following deposition of the vacuum-plasma coatings (TiCr)N, (ZrCrHf)N and other.

scholarly journals A Comparative Study of Adhesion Evaluation Methods on Ophthalmic AR Coating Lens

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 979
Author(s):  
Xin Zhang ◽  
Wei Ma ◽  
Songjin Zhang ◽  
Hongliang Huang ◽  
Liu Ouyang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Comparative Study ◽  
Metal Oxides ◽  
Visual Inspection ◽  
Cutting Tool ◽  
Evaluation Methods ◽  
Thermal Expansion Coefficients ◽  
Light Waves ◽  
Expansion Coefficients ◽  
Ar Coating

Ophthalmic resin lenses are widely used to correct myopia and defend harmful light waves. Ophthalmic lens with anti-reflective (AR) coating has become the mainstream product in the lens market. The AR coating is composed by inorganic metal oxides, which is very different to the organic lens substrate in thermal expansion coefficients. In a normal wearing environment, coating delaminating often occurs resulting that AR function is disabled. How to evaluate adhesion of the AR coating is important. In this paper, a specially designed cutting tool was used to scratch two grids on each surface of the lens. The peel off operation was carried out with the tape within specified adhesion range. The coating detachment was evaluated by visual inspection and microscopy based on the methods defined in ISO 2409 and GB 10810.4, the applicability was compared and discussed.

Contact-Driven Crack Formation in Dental Ceramic Materials

2006 ◽  
pp. 1257-1260
Author(s):  
Wei Li ◽  
Qing Li ◽  
Jeffery Loughran ◽  
Michael Swain ◽  
Ionut Ichim ◽  
...  
Keyword(s):  
Crack Formation ◽  
Ceramic Materials ◽  
Dental Ceramic
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