Quenching induced fracture behaviors of CVD-grown polycrystalline molybdenum disulfide films

RSC Advances ◽  
2016 ◽  
Vol 6 (64) ◽  
pp. 59816-59822 ◽  
Author(s):  
Song Hao ◽  
Bingchu Yang ◽  
Yongli Gao
Keyword(s):  
Molybdenum Disulfide ◽  
Fracture Behavior ◽  
Transgranular Fracture ◽  
Fracture Behaviors ◽  
Polycrystalline Molybdenum

The mixed intergranular and transgranular fracture behavior of CVD-grown polycrystalline MoS2atomic layers has been investigated using multiple techniques.

Contact Fracture Behaviors of Ti3SiC2 Synthesized by Hot Pressing Using TiCx and Si Powder Mixture

2005 ◽  
Vol 486-487 ◽  
pp. 217-220
Author(s):  
Sung Sic Hwang ◽  
Sang Whan Park ◽  
Seong Jai Cho ◽  
Dong Bok Lee
Keyword(s):  
Plastic Deformation ◽  
Fracture Behavior ◽  
Hertzian Contact ◽  
Coarse Grained ◽  
Vickers Indentation ◽  
Hertzian Indentation ◽  
Fine Grained ◽  
Fracture Behaviors ◽  
Hertzian Contact Stress ◽  
Contact Fracture

The contact fracture behaviors of fine-grained Ti3SiC2 and coarse-grained high purity Ti3SiC2 are examined by the Hertzian indentation and Vickers indentation technique. The Vickers hardness of bulk Ti3SiC2 is as low as 5.3~6.3 Gpa, and the Hertzian contact stress-strain curves for Ti3SiC2 deviate much from linearity, which resembles the fracture behavior of a ductile metal rather than a brittle ceramic. The contact damages by both Vickers indentation and Hertzian indentation reveal a fairly good plastic deformation nature of Ti3SiC2. Un-reacted TiCx in fine-grained Ti3SiC2 may impede the plastic deformation by slip along basal plan inside Ti3SiC2 grain, making Ti3SiC2 less plastic under loading.

Analysis for Fracture Behavior of Compactor Grinding Tooth Forging Die Based on Finite Element Method

2011 ◽  
Vol 189-193 ◽  
pp. 2491-2494
Author(s):  
Yong Shao ◽  
Ji Zhou ◽  
Ping Yi Guo
Keyword(s):  
Fracture Behavior ◽  
Local Stress ◽  
Maximum Load ◽  
Local Stress Concentration ◽  
Forging Process ◽  
Stress Changes ◽  
Fracture Behaviors ◽  
Plastic Analysis ◽  
Die Stress ◽  
Forging Die

For forging die fracture behaviors during the actual forging process of compactor grinding tooth, the fully forging process has been simulated based on FEM. Die stress changes and distributions were analyzed in details through two related simulation processes. The maximum load acting on the die which type is ideal rigid body predicted firstly. Then, the die stress can be obtained by the elastic-plastic analysis when the die bears maximum load. Results show that Local stress concentration beyond ultimate strength of material causes the fracture of lower die.

Numerical Simulation of Granite on Pre-Stressed Machining by Discrete Element Method (DEM)

2013 ◽  
Vol 372 ◽  
pp. 646-649 ◽  
Author(s):  
Yong Ye ◽  
Liang Kang
Keyword(s):  
Discrete Element Method ◽  
Fracture Behavior ◽  
Discrete Element ◽  
Machining Process ◽  
Particle Model ◽  
Transgranular Fracture ◽  
Transverse Cracks ◽  
Bonded Particle Model ◽  
Radial Cracks ◽  
Element Method

The bonded particle model (BPM) of granite for pre-stressed machining is build by using the discrete element method (DEM). This model can not only descript the intergranular fracture behavior but also the transgranular fracture behavior of the granite. The processes of crack propagation under different pre-stressed machining conditions are studied by means of DEM simulation. Damages and cracks of surface/subsurface are also observed. The simulation results show that, while the magnitude of pre-stress is controlled in a certatin range, the number of radial cracks reduce as the increasing of pre-stress magnitude, contray to the transverse cracks. It could be seen that maching damage is decreased and surface quality is improved by applying the pre-stressed machining method, and the discrete element method is an effective way to simulate the machining process of granite.

Pressure induced anisotropy of electrical conductivity in polycrystalline molybdenum disulfide

2006 ◽  
Vol 252 (22) ◽  
pp. 7941-7947 ◽  
Author(s):  
V. Sánchez ◽  
E. Benavente ◽  
V. Lavayen ◽  
C. O’Dwyer ◽  
C.M. Sotomayor Torres ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Molybdenum Disulfide ◽  
Induced Anisotropy ◽  
Polycrystalline Molybdenum

scholarly journals COMPARISON OF FRACTURE BEHAVIOR OF SHARP WITH BLUNT CRACK TIP IN NANOCRYSTALLINE MATERIALS BY MOLECULAR DYNAMICS SIMULATION

2012 ◽  
Vol 05 ◽  
pp. 410-417 ◽  
Author(s):  
MOVAFFAQ KATEB ◽  
KAMRAN DEHGHANI
Keyword(s):  
Molecular Dynamics ◽  
Nanocrystalline Materials ◽  
Fracture Behavior ◽  
Md Simulation ◽  
Crack Tip ◽  
Dislocation Nucleation ◽  
Dynamics Simulation ◽  
Blunt Crack ◽  
Pile Up ◽  
Fracture Behaviors

Molecular Dynamics (MD) simulation was used to figure out the fracture behaviors of nanocrystalline materials (NCM). The simulation was based on more than 13 thousand atoms considered for two systems with sharp and blunt crack tip in NCM. Their atomic level resolution provides novel insights into the fracture behavior of NCM. The results show semi brittle manner for both sharp and blunt tips. Dislocation nucleation and pile up at grain boundary (GB), lead to forming voids at GB. Merging mechanism of voids ahead of crack tip causes crack growth.

Influence of Microstructure on the Fracture Mechanism and Mechanical Behavior in 7010 and 7150 Alloys

2006 ◽  
Vol 324-325 ◽  
pp. 463-466
Author(s):  
Xi Gang Fan ◽  
Da Ming Jiang ◽  
Chang Li Wang ◽  
Yong Liang Guo ◽  
Xing Qiu Liu
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Fracture Behavior ◽  
Compact Tension ◽  
Transgranular Fracture ◽  
Plane Strain Fracture Toughness ◽  
Ageing Treatment ◽  
Cu Alloys ◽  
Intermetallic Particles ◽  
Strain Fracture

The effect of ageing treatment and coarse intermetallic particles on the compromise between the toughness and the yield strength of 7010 and 7150 aluminum alloys (Al-Zn-Mg-Cu alloys) are investigated. Plane-strain fracture toughness tests were performed on the compact-tension specimens of L-T orientation. The fracture toughness of 7010 alloy was higher than that of 7150 alloy at the same ageing treatment. The 7150 alloy contain a greater amount of coarse Cu-bearing particles, which deteriorate the fracture behavior and decrease the ageing hardening ability of the alloy. The toughness of the both alloys increased greatly for the overaged condition as compared to that for the T6 condition. Two dominant mechanisms of failure occur: microvoid-induced transgranular fracture and intergranular fracture modes, and the former becomes more important in the overaged ageing conditions.

Temperature and Orientation Dependence of Fracture Behavior of Directionally Solidified Duplex-Phase Crystals Composed of Ni3X-Type Intermetallic Compounds

2006 ◽  
Vol 512 ◽  
pp. 67-72 ◽  
Author(s):  
Koji Hagihara ◽  
Naoyuki Yokotani ◽  
Yukichi Umakoshi
Keyword(s):  
Fracture Toughness ◽  
Temperature Dependence ◽  
Lamellar Structure ◽  
Fracture Behavior ◽  
Orientation Dependence ◽  
Directionally Solidified ◽  
Bending Tests ◽  
Three Point Bending ◽  
Controlling Mechanism ◽  
Fracture Behaviors

Fracture behaviors of three directionally solidified (DS) duplex-phase alloys composed of Ni3Nb(D0a)/Ni3Al(L12), Ni6TaAl(D024)/Ni3Al(L12) and Ni3Ti(D024)/Ni3Si(L12) phases, respectively were investigated by three-point bending tests, focusing on temperature and orientation dependence. The temperature-toughness relation showed dissimilar curves depending on alloy. The increasing rate of fracture toughness was the highest in the Ni3Al/Ni3Nb alloy with fine lamellar structure and was the lowest in the Ni3Al/Ni6TaAl alloy with rod-like precipitates. The controlling mechanism for the temperature dependence of fracture behavior of Ni3Al/Ni3Nb alloys was discussed.

Impact Fracture Behavior of Ceramics and PE-Fiber-Reinforced Mortars

2011 ◽  
Vol 484 ◽  
pp. 75-81
Author(s):  
Yasuhiro Tanabe ◽  
Masayoshi Yamada ◽  
Akihiro Sasoh ◽  
Minoru Kunieda ◽  
Kiyoto Sekine ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Boron Carbide ◽  
Intergranular Fracture ◽  
Fracture Behavior ◽  
The Other ◽  
Transgranular Fracture ◽  
Foreign Object ◽  
Fiber Reinforced ◽  
Impact Fracture Behavior ◽  
Energy Consuming

Ceramics will be used for power generating systems in the next generation. When they are used in this system, damage due to foreign object is inevitable. However, few systematic and comprehensive investigations have been reported on this subject. Various ceramics including fiber-reinforced mortars were investigated to understand their behavior when impacted by a spherical projectile. The volume of the cone cracks was large in ceramics which underwent transgranular fracture, while it was small in which underwent an intergranular one. Even though the energy consuming ability by the formation of surfaces was low up to 3.5% of the kinetic energy of a projectile, this ability increased with the ratio of the intergranular fracture to the transgranular one. Boron carbide showed a lower pressure as compared to the other ceramics. Fiber reinforcing increased the ballistic limits, but no clear advantage was suggested when absorbing the kinetic energy of a projectile far over its limits.

scholarly journals Fracture behaviors of pre-cracked monolayer molybdenum disulfide: A molecular dynamics study

2016 ◽  
Vol 7 ◽  
pp. 1411-1420 ◽  
Author(s):  
Qi-lin Xiong ◽  
Zhen-huan Li ◽  
Xiao-geng Tian
Keyword(s):  
Molecular Dynamics ◽  
Fracture Mechanics ◽  
Size Effect ◽  
Molybdenum Disulfide ◽  
Fracture Strength ◽  
Finite Size ◽  
Dynamics Simulation ◽  
Finite Size Effect ◽  
Fracture Behaviors ◽  
Continuum Fracture Mechanics

The fracture strength and crack propagation of monolayer molybdenum disulfide (MoS2) sheets with various pre-existing cracks are investigated using molecular dynamics simulation (MDS). The uniaxial tensions of pre-cracked monolayer MoS2 sheets with different crack tips, different locations of crack, different crack lengths and angled cracks are simulated and studied. The results show that the configuration of crack tip can influence significantly the fracture behaviors of monolayer MoS2 sheets while the location of crack does not influence the fracture strength. With the increase of crack length, the fracture strength of monolayer MoS2 sheets reduces almost linearly, and the fracture of monolayer MoS2 sheets is transformed from almost brittle to ductile. By making comparison between the MDS results and the predictions of continuum fracture mechanics theories, including Inglis' model, Griffith's model with and without finite size effect, it is found that MDS results agree well with the predictions of Griffith's model with finite size effect, differ from the predictions of Inglis' model and Griffith's model without finite size effect. Finally, the MDS results of monolayer MoS2 sheets with different angled crack are also analyzed based on the continuum fracture mechanics model.

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