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Online since: March 2010
Authors: Wen Bin Sheng, Chun Ming Zhang, Wan Li Gu
Introduction Recently, there have been increasing interests in developing bulk metallic glasses (BMG) with great glass-forming ability (GFA) owing to the unique properties different from that of conventional materials and the potential engineering applications [1-3].
The modified coefficient k leads to a changeable proportion between the two factors and results in a variable GFA.
The indicator γ shows great correlations with some representative glass systems, which reveals the tendency of GFA parameters (Tx, Tg and Tl) affecting GFA.
Otherwise, γ is obtained based on the theoretical analysis with emphasis on the trends without considering the proper proportion between two factors Tg/Tx and Tl/Tx.
In other words, the factors, such as the viscosity, the fusion entropy and the activation energy of the supercooled liquid, give an elevated contribution to GFA.
Online since: October 2004
Authors: Zhi Ming Zhang, Fang Hong Sun, Xiao Gang Jian, Ming Chen, Y.P. Ma
Zhang School of Mechanical Engineering, Shanghai Jiao Tong University, 200030 Shanghai, China a jianxgg@sjtu.edu.cn Keywords: Diamond Thin Film, Tungsten Carbide Substrates, WC Grain Size Abstract.
Different trademarks of tungsten carbide materials have different chemical component, grain size and mechanical performance and are adoptable to different engineering fields.
Among all factors influencing the performances of tungsten carbide materials, grain size may become more attentive one.
Table 1 Chemical compositions and properties of WC-Co substrates WC-Co Average size of Nominal composition Density Hardness Transverse rupture grade WC powder[µm] [wt.%] [g·cm-3] [HRA] strength [MPa] 1(K01) 0.5 94%WC-6%Co 14.85 93.0 2700 2(K10) 1.5 94%WC-6%Co 14.95 91.5 2500 3(K20) 3.0 94%WC-6%Co 14.95 91.0 2600 Results and Discussion Pretreatment and Effect of WC Grain Size on Substrate Pretreatment.
Conclusions These results indicated that the WC grain size of substrate plays an important role in determining the performance of diamond coatings by affecting the adhesion of diamond coatings to the WC-Co substrate and the surface roughness of diamond coatings, and there existed tightness relations among them, which were very important for the selection of raw tungsten carbide materials for the fabrication of diamond-coated tools.
Online since: March 2004
Authors: Kyeong Ho Baik, Jun Ho Jang, S.Y. Hwang
Recently, bulk nanostructured WC-Co materials where WC particles of <100 nm embedded in Co matrix exhibit enhanced mechanical properties including hardness and wear resistance [1], compared to conventional micron-sized materials.
The formation of these additional phases adversely affects hardness, toughness and wear resistance.
Consequently, major factors affecting the final phase distribution of the sprayed coatings are (i) chemical composition, size and morphology of the feedstock powder and (ii) spraying condition, particularly spraying atmosphere and spraying parameters.
Online since: June 2014
Authors: Guirong Li, Yu Tao Zhao, Hong Ming Wang, Yu Hua Cui, Cong Xiang Peng, Rui Zheng, Yue Ming Li, Pei Si Li
Besides the excellent properties of matrix, fine particles play a role of dispersion and fine grain reinforcement.
Ultimately, according to the theoretical analysis, when solid metal or alloy material is subject to strong pulsed magnetic impact, the accompanied magneto plastic effects will have significant influence on the microstructure and properties.
In this paper, particles reinforced Al-Zn-Mg-Cu aluminum composite material at solid state is selected as subject and treated under a pulsed electromagnetic field, aiming to explore the microstructure evolution, properties and their inherent relationship, meanwhile, enrich the theoretical system of material electromagnetic processing.
It follows that the mechanical properties of macroscopic diamagnetic crystals with structural defects containing paramagnetic centers can be significantly affected by magnetic field.
It is specially mentioned that the action of random network local barriers on the dislocation motion is determined by many factors, such as the ionic radius, charge, spin, and number of impurity atoms in the complex.
Online since: May 2012
Authors: Shao Jun Bai, Hai Ying Shen, Shu Ming Wen, Jiu Shuai Deng, Mei Fang Xie
It has a wide range of negative influences on steel properties.
For example, sulfur imposes adverse effects on thermal processing, mechanical properties, weldability, and so on [5].
The most appropriate process flow depends on concentrate properties, difficulty of methods used, and costs.
Considering the ore properties, a joint process of magnetic separation and flotation was carried out.
The interactions between different magnetic intensities and different kinds of mineral ores vary, thereby affecting iron grade and iron recovery.
Online since: June 2014
Authors: Arkanti Krishnaiah
The properties of the materials are strongly dependent on the shear plastic deformation behavior during equal channel angular extrusion (ECAE), which is controlled mainly by die geometry, material properties, and the friction between billet and the die.
Novel properties like superplastic behavior can be attained in some materials [3, 4].
In order to develop the simulations a deformable sample was used, in which the properties for commercial purity copper (stress-strain relationship, s = 359 e 0.3144 MPa) have been taken into account.
The material properties like, Young’s modulus 120 GPa and Poisson’s ratio 0.34 are incorporated in the FEM simulation.
The selected positions as well as the frictional conditions will be critical factors in the effective strain.
Online since: December 2010
Authors: Nian Mei Zhang, Gui Tong Yang, Yong Gang Bao
Projectile shape and mechanical properties of target material play very important role in perforating.
Bending deformation energy is caused by the global deformation of thin target and localized failure deformation energy is caused by compression and shear, which are the most important factors in analysis of energy dissipation.
As shown in Fig.6, the decelerations are affected by geometric characteristics of projectile, that is, shank diameter and CRH, and striking velocity.
So the shank diameter is the more important factor than CRH in the optimization design of projectiles.
Cellular Solids: Structure and Properties.
Online since: May 2014
Authors: Wen Jin Zhang, Qi Hua Su, Zhong Ding Cui, Si Le Chen
Based on the mechanical and deformation characteristic of this tall structure, the bottom stories and stories above the strengthened ones are selected as the "key stories" to control the performance of the building.
It is emphasized that the irregular structure of the degree of ductility directly affect the level of deformation.
For structural engineers, structural properties can be explicitly described physical state are: force, displacement (stiffness), velocity, acceleration, energy, and damage.
Displacement based seismic design can be roughly summarized as follows: a method designed by the ductility factor, capacity spectrum method and the method directly based on displacement [4].
Tall building beyond the highly regulated in various regions of the structure of tall buildings, high aspect ratio limit in many ways, using standardized methods does not ensure good design force and deformation properties.
Online since: June 2014
Authors: Ming Xing Guo, Xiao Feng Wang, Ling Yong Cao, Li Cui, Ji Shan Zhang, Lin Zhong Zhuang
Among many properties, the strength and formability of AA6xxx are the most critical for automotive skin applications.
The developed thermomechanical processing significantly affect the texture components, and further affect the r and Δr values.
Among these factors, it is generally believed that when l/d>5 and draught >50%, or l/d<1, the shear texture will be produced in pure aluminum [16].
However, other factors will give a significant influence on the critical lc/d which can result in the formation of shear texture.
Because the same lubricant and rolls were used in the thermomechanical processing, only rolling geometry factor and draught affect the change of texture components.
Online since: October 2008
Authors: Hong Bing Zhu, Xiu Li
Also, absorption of the recycled aggregate influenced durability properties of RAC badly.
Even though much is known about the mechanical properties of the recycled aggregate concrete, an important question remains about its freeze and thaw durability, and it appears that wide-spread utilization of such concrete will be limited until this question is resolved.
That contradiction, along with the limited research on freezing and thawing durability, requires more extensive research to clarify the circumstances in which recycled aggregate concrete may be regarded as frost-resistant and to determine the major factors that affect its durability.
The properties of RAC were given in table 2.
"Mechanical Properties and Durability of Concrete from Recycled Coarse Aggregate Prepared by Crushing Concrete."
Showing 17331 to 17340 of 26166 items