scholarly journals Interfacial Stabilities, Electronic Properties and Interfacial Fracture Mechanism of 6H-SiC Reinforced Copper Matrix studied by the First Principles Method

2021 ◽  
Author(s):  
Yao Shu ◽  
Shao Wen Zhang ◽  
Yong nan Xiong ◽  
Xing Luo ◽  
Jia zhen He ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Charge Density ◽  
First Principles ◽  
Interfacial Fracture ◽  
Copper Matrix ◽  
Ultimate Tensile Stress ◽  
Partial Density ◽  
Interfacial Mechanics ◽  
Interfacial Energies ◽  
First Principles Method

The interfacial mechanics and electrical properties of the SiC reinforced copper matrix composites were studied via the first principles method. The work of adhesion (Wad) and the interfacial energies were calculated to evaluate the stabilities of the SiC/Cu interfacial models. The carbon terminated (CT)-SiC/Cu interfaces were predicted more stable than those of the silicon terminated (ST)-SiC/Cu from the results of the Wad and interfacial energies. The interfacial electron properties of SiC/Cu were studied via the charge density distribution, charge density difference, electron localized functions and partial density of the state. The covalent C-Cu bonds were formed based on the results of the electron properties, which further explained the fact that the interfaces of the CT-SiC/Cu are stable than those of the ST-SiC/Cu. The interfacial mechanics of the SiC/Cu were investigated via the interfacial fracture toughness and ultimate tensile stress, and the results indicate that both CT- and ST-SiC/Cu interfaces are hard to fracture. The ultimate tensile stress of the CT-SiC/Cu is nearly 23GPa, which is smaller than those of the ST-SiC/Cu of 25 GPa. The strains corresponding to their ultimate tensile stresses of the CT- and ST-SiC/Cu are about 0.28 and 0.26, respectively. The higher strains of CT-SiC/Cu indicate their stronger plastic properties on the interfaces of the composites.

scholarly journals Interfacial Stabilities, Electronic Properties and Interfacial Fracture Mechanism of 6H-SiC Reinforced Copper Matrix Studied by the First Principles Method

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 51
Author(s):  
Yao Shu ◽  
Shaowen Zhang ◽  
Yongnan Xiong ◽  
Xing Luo ◽  
Jiazhen He ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Charge Density ◽  
First Principles ◽  
Interfacial Fracture ◽  
Copper Matrix ◽  
Ultimate Tensile Stress ◽  
Partial Density ◽  
Interfacial Mechanics ◽  
Interfacial Energies ◽  
First Principles Method

The interfacial mechanics and electrical properties of SiC reinforced copper matrix composites were studied via the first principles method. The work of adhesion (Wad) and the interfacial energies were calculated to evaluate the stabilities of the SiC/Cu interfacial models. The carbon terminated (CT)-SiC/Cu interfaces were predicted to be more stable than those of the silicon terminated (ST)-SiC/Cu from the results of the Wad and interfacial energies. The interfacial electron properties of SiC/Cu were studied via charge density distribution, charge density difference, electron localized functions and partial density of the state. Covalent C-Cu bonds were formed based on the results of electron properties, which further explained the fact that the interfaces of the CT-SiC/Cu are more stable than those of the ST-SiC/Cu. The interfacial mechanics of the SiC/Cu were investigated via the interfacial fracture toughness and ultimate tensile stress, and the results indicate that both CT- and ST-SiC/Cu interfaces are hard to fracture. The ultimate tensile stress of the CT-SiC/Cu is nearly 23 GPa, which is smaller than those of the ST-SiC/Cu of 25 GPa. The strains corresponding to their ultimate tensile stresses of the CT- and ST-SiC/Cu are about 0.28 and 0.26, respectively. The higher strains of CT-SiC/Cu indicate their stronger plastic properties on the interfaces of the composites.

scholarly journals First-Principles Calculations on Atomic and Electronic Properties of Ge/4H-SiC Heterojunction

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Bei Xu ◽  
Changjun Zhu ◽  
Xiaomin He ◽  
Yuan Zang ◽  
Shenghuang Lin ◽  
...  
Keyword(s):  
Charge Density ◽  
Electronic Properties ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculation ◽  
Partial Density ◽  
Total Charge ◽  
Relaxation Energy ◽  
Total Charge Density

First-principles calculation is employed to investigate atomic and electronic properties of Ge/SiC heterojunction with different Ge orientations. Based on the density functional theory, the work of adhesion, relaxation energy, density of states, and total charge density are calculated. It is shown that Ge(110)/4H-SiC(0001) heterointerface possesses higher adhesion energy than that of Ge(111)/4H-SiC(0001) interface, and hence Ge/4H-SiC(0001) heterojunction with Ge[110] crystalline orientation exhibits more stable characteristics. The relaxation energy of Ge(110)/4H-SiC(0001) heterojunction interface is lower than that of Ge(111)/4H-SiC(0001) interface, indicating that Ge(110)/4H-SiC(0001) interface is easier to form at relative low temperature. The interfacial bonding is analysed using partial density of states and total charge density distribution, and the results show that the bonding is contributed by the Ge-Si bonding.

scholarly journals Mechanical and Electronic Properties of DNTF Crystals under Different Pressure

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1180
Author(s):  
Hai Nan ◽  
Xianzhen Jia ◽  
Xuanjun Wang ◽  
Heping Liu ◽  
Fan Jiang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
Electronic Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Great Influence ◽  
Shear Resistance ◽  
Variation Trend ◽  
Lattice Constants ◽  
First Principles Method

In the present study, the effects of pressure on the structure, elastic properties and electronic structure of DNTF compounds are studied using the first principles method. It is found that pressure has a great influence on lattice constants. When the pressure reaches 80 GPa, the structure of DNTF changes suddenly. The variation trend of C11, C22 and C33 values is consistent with that of pressure. In addition, pressure can improve the compressibility and shear resistance of the DNTF compound. The pressure can reduce the bandgap and further increases the charge density, causing DNTF to decompose and explode.

Topology of charge density and elastic anisotropy of Ti3SiC2 polymorphs

2005 ◽  
Vol 20 (5) ◽  
pp. 1180-1185 ◽  
Author(s):  
R. Yu ◽  
X.F. Zhang ◽  
L.L. He ◽  
H.Q. Ye
Keyword(s):  
Charge Density ◽  
Young’S Modulus ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Young's Modulus ◽  
The Other ◽  
Full Potential ◽  
Density Topology ◽  
Other Hand ◽  
First Principles Method

Using an all-electron, full potential first-principles method, we have investigated the topology of charge density and elastic anisotropy of Ti3SiC2 polymorphs comparatively. By analyzing the charge density topology, it was found that the Ti–Si bonds are weaker in β than in α, resulting in a destabilizing effect and lower Young’s modulus in directions between a and c axes for β. On the other hand, the Si–C bonds (absent in α) are formed in β in the c direction. The formation of the Si–C bonds not only mitigates the destabilizing effect of the weaker Ti–Si bonds, but also results in larger Young’s modulus in the c direction. In contrast to the high elastic anisotrophy, the elastic anisotropy of Ti3SiC2 is very low.

scholarly journals First-principles calculation of atomic structure, stability and electronic structure of TaB2/SiC interface

2020 ◽  
Author(s):  
Gong Cheng ◽  
Yuqing Xiong ◽  
Hui Zhou ◽  
Yanchun He ◽  
Kaifeng Zhang ◽  
...  
Keyword(s):  
Charge Density ◽  
Atomic Structure ◽  
First Principles ◽  
Dominant Role ◽  
Covalent Bond ◽  
First Principles Calculation ◽  
Work Of Adhesion ◽  
Structure Stability ◽  
Partial Density ◽  
Electronic Interaction

Abstract The atomic structure, interface stability and electronic interaction of TaB2(0001)/SiC(111) interfaces were investigated by first principles study. The study found that the termination atom and stacking position are the key factors affecting the bonding strength and stability of the interface. On the basis of considering work of adhesion (Wad) and interfacial energy (γint), the Ta-TaB2/C-SiC centre-site stacked (Ta CS-C) and B-TaB2/C-SiC center-site stacked (B-CS-C) configurations were recognized as the most stable structures from ten different interface models. Electronic interaction of the two most stable interfaces were revealed by analyzing the charge density distribution, charge density difference and partial density of states (PDOS), and it was found that ionic and metallic bond coexisted in Ta CS-C interface, while covalent bond played a dominant role in B-CS-C interface.

Investigation of Functionally Graded Aluminium A356 Alloy and A356-10%SiCp Composite for Hydro Turbine Bucket Application

2016 ◽  
Vol 26 ◽  
pp. 30-46 ◽  
Author(s):  
Williams S. Ebhota ◽  
Akhil S. Karun ◽  
Freddie L. Inambao
Keyword(s):  
Heat Treatment ◽  
Tensile Stress ◽  
Centrifugal Casting ◽  
A356 Alloy ◽  
Casting Process ◽  
Ultimate Tensile Stress ◽  
Functionally Graded ◽  
Cnc Machining ◽  
Mould Material ◽  
Turbine Bucket

The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.

Effect of Boron and Hydrogen on the Electronic Structure of Ni3Al

1993 ◽  
Vol 319 ◽  
Author(s):  
N. Kioussis ◽  
H. Watanabe ◽  
R.G. Hemker ◽  
W. Gourdin ◽  
A. Gonis ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
First Principles ◽  
Electronic Structure Calculations ◽  
Interstitial Site ◽  
Octahedral Interstitial Site ◽  
Interstitial Region ◽  
Ordered Intermetallic ◽  
Lmto Method ◽  
Structure Calculations

AbstractUsing first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial boron and hydrogen on the electronic structure of the L12 ordered intermetallic Ni3A1. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound “pure” Ni3AI crystal: Charge is depleted at Ni and Al sites and enhanced in interstitial region. Substitution of Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between certain atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.

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