The Material Discontinuous Zone Influence on the Behavior of Crack Propagation in the Matrix Material

2013 ◽  
Vol 345 ◽  
pp. 263-267
Author(s):  
Zhi Jia Sun ◽  
You Tang Li
Keyword(s):  
Crack Propagation ◽  
Deflection Angle ◽  
Matrix Material ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Propagation Path ◽  
Propagation Behavior ◽  
The Matrix ◽  
The Deflection Angle ◽  
Simulation Results

A numerical method to simulate the crack propagation is presented in this paper. The FEM is used to estimate the influence of the material discontinuous zone on the propagation behavior of the crack placed in close to it in the matrix. The crack propagation paths in the matrix with different material discontinuous zone are simulated. The simulation results show that the crack propagation path will deviate toward the material discontinuous zone when the crack grows in closed to it and the property of the material discontinuous zone influences the deflection angle and the crack propagation rate.

scholarly journals Crack Propagation Behavior of a Ni-Based Single-Crystal Superalloy during In Situ SEM Tensile Test at 1000 °C

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tensile Test ◽  
Single Crystal ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Single Crystal Superalloy ◽  
Propagation Path ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.

Quasi-Static Simulation of Crack Propagation on Elastic Material with Material Discontinuous Zone

2013 ◽  
Vol 746 ◽  
pp. 211-214
Author(s):  
Zhi Jia Sun ◽  
You Tang Li
Keyword(s):  
Crack Propagation ◽  
Deflection Angle ◽  
Crack Path ◽  
Circumferential Stress ◽  
Propagation Direction ◽  
Propagation Path ◽  
Stress Theory ◽  
Fem Method ◽  
The Matrix ◽  
Simulation Results

A numerical method to simulate the crack propagation based on the maximum circumferential stress theory is presented in this paper. The FEM method is used to estimate the influence of the material discontinuous zone on the propagation path of the crack placed in close to it in the matrix. When the crack grows, the FEM method uses the maximum circumferential stress theory to determine the propagation direction and the elements re-meshing program to ensure the accuracy of the crack-tip stress field. The crack propagation paths in the matrix with different material zone are simulated by the method. The simulation results show that the property of the material discontinuous zone influences the maximum deflection angle and its size influences the length of the deflected crack path.

Stress corrosion property of 304 stainless steel and Q345 steel laser-MAG hybrid welded joints

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040057
Author(s):  
Hang Lv ◽  
Guoqing Gou ◽  
Zhenghong Fu ◽  
Wei Gao
Keyword(s):  
Stainless Steel ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Corrosion Property ◽  
304 Stainless Steel ◽  
Propagation Path ◽  
Crack Propagation Path ◽  
Immersion Testing

The stress corrosion cracking (SCC) property of laser-MAG hybrid welded 304 stainless steel and Q345 steel was evaluated through cycle-immersion testing in 3.5 wt.% NaCl solution. The average SCC crack propagation rate of different zones under different initial stress intensity factors was calculated, and the SCC fracture and crack propagation path were observed. The microstructure and mechanical properties of the weld joint have also been examined. The result indicates that the fusion zone (FZ) is extremely prone to SCC. The average SCC crack propagation rate in FZ is [Formula: see text] mm/h, while no obvious SCC was found in the base metal (BM) and heat-affected zone (HAZ). The steel BM and HAZ may also suffer SCC, but not as fast as in FZ. Grooves caused by SCC were found on the fracture surface with a large amount of corrosion products accumulated close to the interface between the pre-crack section and SCC section. Crystallized-sugar-shaped pattern was found on the SCC zone of FZ. Crack jumping, deflection and crack closure occurred in the crack propagation path. Martensite on the FZ was considered to be the major reason that the FZ has a higher SCC propagation rate.

Reasearch on Heat-Shocking Resistance of SiC(w)/ZrO2-MoSi2 Ceramic Composites

2010 ◽  
Vol 97-101 ◽  
pp. 1595-1600
Author(s):  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Zi Qian Liu ◽  
Wen He ◽  
Jian Jun Zhang
Keyword(s):  
Crack Propagation ◽  
Phase Transfer ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Ceramic Composites ◽  
Propagation Path ◽  
Sic Nanoparticles ◽  
Sic Whiskers ◽  
Hot Pressing Sintering ◽  
Better Than

The heat-shocking resistance of SiC(w)/ZrO2-MoSi2 ceramic composites prepared by hot-pressing sintering was studied by indentation-quench method together with the calculation of the crack propagation rate of ceramic nanocomposites. The results showed that the crack propagation rate of MoSi2 matrix ceramics samples decreased remarkably with the addition of ZrO2 and SiC nanoparticles. The crack propagation rate of SiC(w)/ZrO2-MoSi2 ceramic composites was obviously lower than that of ZrO2-MoSi2 ceramic composites, which revealed that the synergism between SiC(w) and ZrO2 was more advantageous to enhance the heat-shocking resistance of MoSi2 ceramic. Moreover, the ability of ZrO2 particles to hinder the heat-shocking crack propagation was better than that of SiC whiskers. The synergism between SiC(w) and ZrO2 changed the crack propagation path and shape in MoSi2 ceramics. The mechanisms of ZrO2 to improve the heat-shocking resistance of the MoSi2 ceramic were mainly phase transfer toughening, while that of SiC whiskers to improve the heat-shocking resistance of the MoSi2 ceramic were mainly crack deflection and bridge union.

Effect of Calcification on The Fatigue Behavior of Fluorinated Polyurethanes

1999 ◽  
Vol 599 ◽  
Author(s):  
R. S. Benson ◽  
H. J. Kim
Keyword(s):  
Crack Propagation ◽  
Calcium Chloride ◽  
Calcium Salt ◽  
Fatigue Behavior ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fluorinated Polyurethane ◽  
Propagation Behavior ◽  
Tearing Energy ◽  
The Difference

AbstractThe present study compares the fatigue propagation behavior of a fluorinated and nonfluorinated polyurethane-calcium salt blends. The calcium salts used in this study are calcium chloride and hydroxyapatite (HAP). The fatigue crack propagation (FCP) behavior of the polyurethanes exhibited a dependence on the chemical composition of the polymer and calcium salt. The pure non-fluorinated PTMG2000 did no undergo crack propagation. While the fluorinated PTMG2003F exhibit a crack propagation rate of 7.8 × 10-6m/cycle at constant strain amplitude and tearing energy range. The incorporation of calcium chloride into PTMG2000 did not promote any changes in the FCP behavior; while the addition of HAP produced cracks with a growth rate of 3.33 × 10-6m/cycle. In the case of PTMG2003F, the addition of calcium chloride did not lead to formation of cracks; while HAP produced a material in which cracks propagated at a rate of 10.0 × 10-6m/cycle. The difference in the response the non-fluorinated and fluorinated polyurethane-calcium salt blends to cyclic loading can be attributed to molecular level variations such as domains disruption and changes in chain orientation at the crack tip.

Crack Propagation Behavior at Sn37Pb-Copper Interface in Low Cycle Fatigue

2007 ◽  
Vol 353-358 ◽  
pp. 2962-2965
Author(s):  
Masao Sakane ◽  
Kazuhiro Itoh ◽  
Yutaka Tsukada ◽  
Kenji Terada
Keyword(s):  
Crack Propagation ◽  
Crack Path ◽  
Low Cycle Fatigue ◽  
Interfacial Crack ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Cycle Fatigue ◽  
Propagation Behavior ◽  
Integral Range ◽  
Crack Propagation Behavior

This paper studies the crack propagation at Sn37Pb-copper interface in push-pull low cycle fatigue. Bonded specimens of Sn37Pb and copper having notch holes with different distances from the interface were fatigued at 313K and the crack propagation paths were observed. Cracks propagated at the interface when the notch hole was near the interface but propagated in the solder when the notch hole was away from the interface. The propagation rate of the interfacial crack was faster than that of non-interface crack. The crack path and crack propagation rate of the two types of cracks were discussed in relation to J integral range calculated by finite element method.

The Fatigue Crack Propagation of Al–Mg–Mn–Zr Alloy with Erbium

2015 ◽  
Vol 1120-1121 ◽  
pp. 1083-1088
Author(s):  
Xin Lei ◽  
Hui Huang ◽  
Huan Wang
Keyword(s):  
Fatigue Crack ◽  
Grain Boundary ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Propagation Path ◽  
Fatigue Crack Propagation Rate ◽  
Second Phase ◽  
Second Phases

This study investigated the fatigue crack propagation of Al–Mg–Mn–Zr alloys with erbium. The research found that in this alloy the crack propagation path prefers to extend along the grain boundary. If there are too many second phases or impurities in the gain boundary, the crack propagation will be influenced. The dispersed Al3(Er, Zr) precipitate in the alloy can act as a core of heterogeneous nucleation to attract Mg, Zn and Al element, and reduce the large brittle Al3Mg2second phase appear on the grain boundary, so the fatigue crack propagation rate can be slow down. In addition, these Al3(Er, Zr) precipitate can pin the dislocation in the alloy to reduce stress concentration at the grain boundary, so it also has some positive effect to the fatigue crack propagation.

Effect of Microscopic Inhomogeneity on Creep-Fatigue Crack Propagation of Transversally Loaded Directionally Solidified Superalloy

2007 ◽  
Author(s):  
Masato Yamamoto ◽  
Takayuki Kitamura ◽  
Takashi Ogata
Keyword(s):  
Crack Propagation ◽  
Crack Path ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Local Deformation ◽  
Transverse Load ◽  
Directionally Solidified ◽  
Propagation Behavior ◽  
Creep Fatigue

Directionally solidified superalloy, which has elongated large grains, is used for a gas-turbine blade because of its high creep strength. Since the grain size is not small enough in comparison with the size of component and crack, the inhomogeneous microstructure strongly affects the crack propagation behavior. The aim of this research is to clarify the microstructural effect in the creep-fatigue under a transverse load. The experiment reveals characteristic crack path and fluctuation of crack propagation rate in detail. Several intergranular sub-cracks initiated ahead of the tip of main crack occasionally connect with each other and form a complicated crack path. The deformation near the crack tip during a loading cycle is highly dependent on the local grain boundary network, grain shape, and crack shape. The magnitude of da/dN is correlated fairly well with that of local deformation in the vicinity of crack tip. This suggests that the stress field near the crack tip governs the crack propagation.

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