Effects of Microcracks in CVD Coating Layers on Cemented Carbide and Cermet Substrates on Residual Stress and Transverse Rupture Strength

1997 ◽  
Vol 119 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Sakae Katayama ◽  
Masayuki Hashimura
Keyword(s):  
Residual Stress ◽  
Coating Layer ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
Tensile Residual Stress ◽  
Transverse Rupture Strength ◽  
Beneficial Effects ◽  
Thermal Expansion Coefficients ◽  
Coating Layers ◽  
Expansion Coefficients

Microcracks were mechanically induced in the CVD coating layers on two types of cemented carbides with different thermal expansion coefficients, and one type of cermet. The microcracks were found to have beneficial effects on residual stress, transverse rupture strength, and chipping resistance during interrupted cutting. Residual stress in the coating on cemented carbide is tensile. Tensile residual stress decreases with increasing microcrack width and decreasing microcrack distance. Induction of 20 μm-distant and 0.025 μm-wide cracks relieves tensile residual stress by about 0.5 GPa, increases transverse rupture strength by about 0.70 GPa, and almost doubles the chipping resistance. Residual stress in the coating on cermet is compressive. Microcracks in the coating layer do not change residual stress or transverse rupture strength.

scholarly journals Effect of Specimen Volume on Transverse-Rupture Strength of WC-10%Co Cemented Carbide

1977 ◽  
Vol 24 (8) ◽  
pp. 232-235
Author(s):  
Hisashi Suzuki ◽  
Teruyoshi Tanase ◽  
Fumio Nakayama ◽  
Koji Hayashi
Keyword(s):  
Rupture Strength ◽  
Cemented Carbide ◽  
Transverse Rupture Strength ◽  
Specimen Volume

Simultaneously high fracture toughness and transverse rupture strength in ultrafine cemented carbide

CrystEngComm ◽  
2013 ◽  
Vol 15 (17) ◽  
pp. 3305 ◽  
Author(s):  
Chongbin Wei ◽  
Xiaoyan Song ◽  
Jun Fu ◽  
Xuemei Liu ◽  
Haibin Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Transverse Rupture Strength

scholarly journals Evolution of the microstructure, residual stresses, and mechanical properties of W–Si–N coatings after thermal annealing

2005 ◽  
Vol 20 (5) ◽  
pp. 1356-1368 ◽  
Author(s):  
A. Cavaleiro ◽  
A.P. Marques ◽  
J.V. Fernandes ◽  
N.J.M. Carvalho ◽  
J.Th. De Hosson
Keyword(s):  
Residual Stress ◽  
Thermal Annealing ◽  
Amorphous Film ◽  
Amorphous Coating ◽  
X Ray Diffraction ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Composition Structure ◽  
The One ◽  
Deposited Film

W–Si–N films were deposited by reactive sputtering in a Ar + N2 atmosphere from a W target encrusted with different number of Si pieces and followed by a thermal annealing at increasing temperatures up to 900 °C. Three iron-based substrates with different thermal expansion coefficients, in the range of 1.5 × 10−6 to 18 × 10−6 K−1 were used. The chemical composition, structure, residual stress, hardness (H), and Young’s modulus (E) were evaluated after all the annealing steps. The as-deposited film with low N and Si contents was crystalline whereas the one with higher contents was amorphous. After thermal annealing at 900 °C the amorphous film crystallized as body-centered cubic α–W. The crystalline as-deposited film presented the same phase even after annealing. There were no significant changes in the properties of both films up to 800 °C annealing. However, at 900 °C, a strong decrease and increase in the hardness were observed for the crystalline and amorphous films, respectively. It was possible to find a good correlation between the residual stress and the hardness of the films. In several cases, particularly for the amorphous coating, H/E higher than 0.1 was reached, which envisages good tribological behavior. The two methods (curvature and x-ray diffraction) used for calculation of the residual stress of the coatings showed fairly good agreement in the results.

Mechanical Properties of WC-Co Cemented Carbide Prepared via Vacuum Sintering

2013 ◽  
Vol 275-277 ◽  
pp. 1917-1920
Author(s):  
Bing Liang Liang ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Nan Jiang
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Relative Density ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
Vacuum Sintering ◽  
Transverse Rupture Strength ◽  
Temperature Range ◽  
Peak Value

WC-Co cemented carbide specimens were prepared via vacuum sintering. The influences of composition and sintering temperature on phase composition, microstructure and mechanical properties of WC-Co cemented carbide were investigated. The results show that dense specimens were obtained in the sintering temperature range of 1280~1400°C and the relative density reached over 95%. Only WC and Co3W3C (-phase) were detected by XRD without any else phases, even though Co. With the ascended sintering temperature, hardness increased and the transverse rupture strength (TRS) ascended to peak value and then descended. WC-Co cemented carbide with excellent mechanical properties (HRA>90, TRS~700MPa and KIC>10MPa•m1/2) were obtained.

Residual Stress in Two Dental Alloys During Porcelain Application

1987 ◽  
Vol 31 ◽  
pp. 255-260
Author(s):  
M. Bagby ◽  
SJ Marshall ◽  
GW Marshall
Keyword(s):  
Residual Stress ◽  
Thermal Expansion ◽  
Residual Stresses ◽  
Casting Process ◽  
Dental Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Dental Restorations ◽  
Expansion Coefficients

Residual stresses in dental castings are widely held to be the cause of distortion and change of fit in ceramic bonded to metal dental restorations. Residual stresses are thought to result from the casting process and from ceramic/metal mismatch of thermal expansion coefficients. Such stresses have not been confirmed experimentally. The purpose of this study was to measure residual stress with x-ray diffraction at the various porcelain application steps for two noble dental alloys with two dental opaque porcelains.

Strain Effects in GaN on Sapphire: Towards a Quantitative Comprehension

1995 ◽  
Vol 395 ◽  
Author(s):  
O. Briot ◽  
J.P. Alexis ◽  
B. Gil ◽  
R.L. Aulombard
Keyword(s):  
Residual Stress ◽  
Structural Characteristics ◽  
Reflectance Spectroscopy ◽  
Strongly Correlated ◽  
Deformation Potential ◽  
Quantitative Investigation ◽  
Growth Ratio ◽  
Sapphire Substrates ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

ABSTRACTWe present here a detailed investigation of the optical properties of GaN epilayers grown by low pressure MOVPE on sapphire substrates, using 2K photoluminescence as well as 2K reflectance spectroscopy. A large series of samples has been grown under eclectic conditions (V/III ratio, growth temperature, nitridation steps,...) which allows us to propose the first semi-quantitative investigation of the sample-dependent band gap energies. This dependence of the bandgap is analyzed in terms of i) residual stress, ii) exciton parameters and iii) deformation potential characteristics of the A, B, C excitons. the residual stress cannot be simply explained in terms of the differences between the thermal expansion coefficients of the various compounds, but are strongly correlated to the V/III growth ratio imposed during the growth, and subsequently to the influence of this parameter at the scale of electronic and structural characteristics of the deposited layers.

scholarly journals Effect of Dissipative and Dispersive DNG Material Coating on the Scattering Behavior of Parallel Nihility Circular Cylinders

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Shakeel Ahmed ◽  
Muhammad Naveed ◽  
Abdul Ghaffar ◽  
Aqeel A. Syed ◽  
Q. A. Naqvi
Keyword(s):  
Plane Wave ◽  
Electromagnetic Scattering ◽  
Iterative Procedure ◽  
Coating Layer ◽  
Circular Cylinders ◽  
Double Negative ◽  
Double Positive ◽  
Different Types ◽  
Coating Layers ◽  
Expansion Coefficients

Electromagnetic scattering from coated nihility circular cylinders, illuminated byE-polarized plane wave, is investigated using an iterative procedure. Cylinders are infinite in length. The boundary conditions are applied on the surface of each cylinder in an iterative procedure in order to solve for the field expansion coefficients. The effect of different types of the coating layers including double positive (DPS) and double negative (DNG) on the alteration of the forward and backward scattering has been observed. Specially, the effect of dispersive and dissipative DNG coating layer has been focused. Numerical verifications are presented to prove the validity of this formulation by comparison with the published literature.

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