The relationship between Palmqvist indentation toughness and bulk fracture toughness for some WC-Co cemented carbides

1979 ◽  
Vol 14 (7) ◽  
pp. 1619-1623 ◽  
Author(s):  
C. T. Peters
Keyword(s):  
Fracture Toughness ◽  
Cemented Carbides ◽  
Indentation Toughness ◽  
The Relationship ◽  
Bulk Fracture

Modified Equation to Predict Leak/Rupture Criteria for Axially Through-Wall Notched X80 and X100 Linepipes Having Higher Charpy Energy

2004 ◽  
Author(s):  
Shinobu Kawaguchi ◽  
Naoto Hagiwara ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Fracture Toughness ◽  
Flow Stress ◽  
Pipe Material ◽  
Test Results ◽  
Absorbed Energy ◽  
Bending Tests ◽  
Full Scale Tests ◽  
Hoop Stresses ◽  
The Relationship ◽  
Modified Equation

A method of predicting the leak/rupture criteria for API 5L X80 and X100 linepipes was evaluated, based on the results of hydrostatic full-scale tests for X60, X65, X80 and X100 linepipes with an axially through-wall (TW) notch. The TW notch test results clarified the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The obtained leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner et al. The comparison revealed that the CVN-based equation was not applicable to the pipes having a CVN energy (Cv) greater than 130 J and flow stress greater than X65. In order to predict the leak/rupture criteria for these linepipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and buffed Charpy V-notch specimens after static 3-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq’ which was defined as follows: (Cv)eq = 4.5 (Cvs)i. The leak/rupture criteria for the X80 and X100 linepipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.

scholarly journals Effect of WC/Co coherency phase boundaries on Fracture toughness of the nanocrystalline cemented carbides

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hongxian Xie ◽  
Xiaoyan Song ◽  
Fuxing Yin ◽  
Yongguang Zhang
Keyword(s):  
Fracture Toughness ◽  
Cemented Carbides ◽  
Phase Boundaries

scholarly journals On The Parameters of Geometric Constraints for Cracked Plates under Tension – Three-Dimensional Problems

2017 ◽  
Vol 22 (4) ◽  
pp. 901-919 ◽  
Author(s):  
M. Graba
Keyword(s):  
Fracture Toughness ◽  
Comparative Analysis ◽  
Crack Front ◽  
External Load ◽  
Three Dimensional ◽  
Geometric Constraints ◽  
Numerical Calculations ◽  
Cracked Plates ◽  
The Relationship ◽  
Actual Fracture

Abstract This paper provides a comparative analysis of selected parameters of the geometric constraints for cracked plates subjected to tension. The results of three-dimensional numerical calculations were used to assess the distribution of these parameters around the crack front and their changes along the crack front. The study also involved considering the influence of the external load on the averaged values of the parameters of the geometric constraints as well as the relationship between the material constants and the level of the geometric constraints contributing to the actual fracture toughness for certain geometries.

scholarly journals Study on Microstructure and Mechanical Properties of WC-10Ni3Al Cemented Carbide Prepared by Different Ball-Milling Suspension

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2224 ◽  
Author(s):  
Minai Zhang ◽  
Zhun Cheng ◽  
Jingmao Li ◽  
Shengguan Qu ◽  
Xiaoqiang Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Ball Milling ◽  
Grain Growth ◽  
Organic Solvents ◽  
Crack Deflection ◽  
Cemented Carbides ◽  
Powder Metallurgy Method ◽  
Microstructure And Mechanical Properties ◽  
Α Al2o3

In this paper, WC-10Ni3Al cemented carbides were prepared by the powder metallurgy method, and the effects of ball-milling powders with two different organic solvents on the microstructure and mechanical properties of cemented carbides were studied. We show that the oxygen in the organic solvent can be absorbed into the mixed powders by ball-milling when ethanol (CH3CH2OH) is used as a ball-milling suspension. This oxygen leads to the formation of α-Al2O3 during sintering, which improves the fracture toughness, due to crack deflection and bridging, while the formation of η-phase (Ni3W3C) inhibits the grain growth and increases the hardness. Alternatively, samples milled using cyclohexane (C6H12) showed grain growth during processing, which led to a decrease in hardness. Therefore, the increase of oxygen content from using organic solvents during milling improves the properties of WC-Ni3Al composites. The growth of WC grains can be inhibited and the hardness can be improved without loss of toughness by self-generating α-Al2O3 and η-phase (Ni3W3C).

scholarly journals Experimental Study on the Effect of Offset Notch on Fracture Properties of Rock under Three-Point Bending Beam

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Qifeng Guo ◽  
Xinghui Wu ◽  
Meifeng Cai ◽  
Shengjun Miao
Keyword(s):  
Fracture Toughness ◽  
Experimental Study ◽  
Tensile Strength ◽  
Peak Load ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Nominal Strength ◽  
Bending Load ◽  
The Relationship ◽  
Rock Beam

To investigate the effects of offset notch on the fracture properties of rock beam under bending load, granite beam specimens with “one single offset notch” and “central and offset double notches” are made. A series of three-point bending beam tests on the specimens are carried out by controlling the displacement rate of central notch. The whole load-displacement (P-CMOD) curves are obtained. Experimental results show that the larger the distance between the offset notch and beam central is, the larger are the peak load and nominal strength of the specimen. The peak load and nominal strength for the “central and offset double notches” specimens are both larger than those for the “single central notch” specimen. A fracture model considering the effect of offset notch is developed, and the relationship between the offset notch parameter, tensile strength, and fracture toughness is established.

Properties of Cryogenic Treated Cemented Carbides (WC-Co)

2020 ◽  
Vol 403 ◽  
pp. 75-89
Author(s):  
Vojtěch Průcha ◽  
David Bricín ◽  
Antonín Kříž ◽  
Zdeněk Jansa
Keyword(s):  
Fracture Toughness ◽  
Cryogenic Treatment ◽  
The Other ◽  
Coarse Grained ◽  
Cemented Carbides ◽  
Polished Surface ◽  
X Ray Diffraction ◽  
Deep Cryogenic Treatment ◽  
Fine Grained ◽  
Disk Test

The present paper explores the effects of deep cryogenic treatment (DCT) on the properties of WC-Co cemented carbides. The investigation involved four different cemented carbide (CC) grades. Two of them were coarse-grained WC with grain sizes larger than 6 μm and binder fractions of 10 and 15 wt. %. The other two were fine-grained with WC grains of 0.5-0.8 μm and the same binder fractions of 10 and 15 wt. %. Their specimens were ground and polished to prepare them for DCT. In each specimen, one half of this polished surface was used for testing the properties of the CC before cryogenic treatment. The post-DCT properties were then determined on the other half. Properties of the cemented carbides prior to and after DCT were studied using optical and scanning electron microscopy, X-ray diffraction, hardness testing according to Vickers scale followed by calculation of fracture toughness KIC and a ball-on-disk test of the wear resistance of the surface. One of the findings was that cryogenic treatment led to a decrease in residual stresses and to lower fracture toughness KIC in the CC.

Effect of Sintering Temperature on Microstructure and Properties of VС/Fe Composite

2012 ◽  
Vol 430-432 ◽  
pp. 978-983
Author(s):  
Guo Jun Zhang ◽  
Zhi Ping Sun ◽  
Li Yan Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Sintering Temperature ◽  
Growth Trend ◽  
Flexure Strength ◽  
Microstructure And Properties ◽  
Whole Process ◽  
Relationship Of ◽  
The Relationship ◽  
Composite Samples

VC/Fe composite samples were fabricated by sintering at 1050, 1100 and 1150°C in vacuum. The microstructure and mechanical properties of samples were examined, and the relationship of structure and mechanical properties for VC/Fe composite sintered at different temperature were studied. The results show that fracture toughness, hardness and density is increasing obviously at 1050-1100°Cwith the increasing sintering temperature, but the growth trend increases slowly at 1100-1150°C; in whole process with temperature increased, Flexure strength heighten trend obviously. The microstructure of VC/Fe composite changed from particles piled up together to the microstructure particles closely, VC particles set gradually into Fe with temperature increased, and the gap reduced gradually.

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