Search results

Porous AlN Ceramics Fabricated by Carbothermal Reduction Yuan Lu1,2, a, Jinglong Li1 , Jianfeng Yang3, b* and Peng Li1 1 Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China; 2 Xi’an Special Equipment Inspection Institute, Xi'an, Shaanxi 710065, China; 3 State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China aluyuan19801104@163.com, byang155@mail.xjtu.edu.cn Keywords: Ceramics, Porosity, Microstructure, Sintering, Mechanical properties.
The influences of sintering additives and sintering temperature on the microstructure and mechanical properties of porous AlN ceramics were investigated.
Excellent properties make porous AlN ceramic promising candidates for many applications.
Effects of sintering additives and sintering temperature on microstructures and mechanical properties of porous AlN ceramics were investigated.
The influences of sintering additives on microstructure and mechanical properties were investigated.

Structure and Properties of Laser-Welded Joints from High-Strength Steels O.
At present time, high-strength steels of more than 700 MPa yield strength, providing high level of mechanical properties, are used in manufacture of the critical welded structures.
However, structure and phase composition of the weld metal and heat affected zone (HAZ) can significantly change as a result of effect of thermal welding cycle, and, respectively, influence the level of mechanical properties and crack resistance of the welded joints [4-6].
Strengthening, caused by structural parameters, along the welding zone of welded joints from 14KhGN2MDAFB steel Area of investigation Strengthening Weld I zone HAZ Δσg [MPa] 80 115 ΔσS [MPa] 300…500 500…750 Δσds [MPa] 59…188 106…188 ∑Ds(g, S, ds) [MPa] 604 887 Thus, procedures for quantitative evaluation of properties of metal strength by specific structural parameters allow predicting welded joint quality at formation of different type structures in the welding zone and detecting of structural factors, having main effect on mechanical properties change.
Belov Phase Transformations and Properties of Steel in Welding.

We should determine the depth of hole to avoid measuring the scope non-tectonic stress can not affect and affecting stress field analysis of regional study area.
Comparing with the regional orientation of the principal stress, the orientation of the principal stress near the fracture often occurs different degree of changes, and changes in the range are from a few degrees to near 90 ° [2] . 1.5.2 Some questions after measuring Geo-stress (1) Influence factors of Geo-stress measurement state and reliability analysis Regional geological background and various affecting factors should be analysis as for the state of Geo-stress.
A measured values lack of geological background and influencing factors may be misleading [3]
(2) Rock mechanical properties impact on Geo-stress measurement and its correction analysis Different lithologies intensity may lead to the measured data difference.
Due to interaction of various influencing factors near the surface, Geo-stress often superimposes with non-tectonic stress.

In modern construction, a large variety of small architectural forms are used, for the production of which cement concrete is traditionally used, which should have improved physical and mechanical properties and decorative properties, while having a low cost.
Improvement of these properties is achieved through the use of carbonate additives - highly dispersed chalk.
Small architectural forms, during the period of operation, are exposed to the action of atmospheric factors (sun, precipitation, wind, frost) and the influence of the urban environment - dust, gas pollution, vibrations from different types of transport.
Therefore, the material used for such products must have high performance, decorative properties and have improved indicators of durability [2-3].
Based on the foregoing, it is assumed that the addition of highly dispersed chalk affects the structure formation of cement stone due to the formation of new compounds that compact the structure, the formation of optimal grain packing, therefore the durability and operational properties of concrete are improved.

Introduction Level fluctuation is the main factor of bonding breakout, the unreasonable flow field in the Mould distribution is one of the important reason inducing level fluctuation.
Based on the focal point, ignoring some secondary factors, making following hypothesis for the liquid steel flow field in the mold: (1) Don’t think about the shell’s distribution, It is produced by flow field distribution; (2) It is stable distribution under normal draw speed, this flow field is steady state , none of the business with time; (3) Liquid steel’s Thermodynamic Properties is constant; Thermodynamic Properties and boundary conditions Based on 1530℃, the Thermodynamic Properties that relates to calculation: Liquid steel density is 7200kg/m3;liquid steel viscosities is 0.0062kg/(m﹒s).
The selection of calculation scheme For arguing how the submerged nozzle output angle affects liquid steel flow field, the following output angles are adopted: downward 16°(now is used) , downward 13°, downward8°, 0°.
Actually the factors which affect Flow Field in the Mold include draw speed, submerged nozzle(outlet position) , outlet style and so on, among them draw speed is the most important factor.
The cross-section 1800×250mm is completely different, injecting flow strike the wall directly, It will appear two obvious flow, flow condition will seriously affected by mold wall.

It causes chemical inhomogeneity in the structure and hence is detrimental to the mechanical properties.
The present work is pursued in this direction and the paper reports various factors that affect the formation and control of Laves phase as a result of segregation in K418 and 42CrMo dissimilar metal laser welding.
Laves phase is detrimental to mechanical properties of joint.
It should be noted that segregation is a time-dependent phenomenon and hence is strongly affected by the weld cooling rate, as influenced by various factors like heat input etc.
The factors G and R also control the amount of supercooling during weld solidification, which determines the extent of segregation.

The magnitude of the plastic shrinkage and the increase of the associated mechanical properties depend on the different parameters (porosity, elastic properties and structural features).
In the literature, the elastomechanical properties of aerogels are tested either by sound velocity measurements [3, 4,]), or by static techniques (uniaxial compression [5], diametric compression [6] and three point bending [7].
Two kinds of information will be analyzed: the evolution of the elastic properties due to plastic shrinkage and the associated structural changes by small angle scattering ( SAXS).
The elastic properties will give insight into the evolution of the connectivity, and the SAXS data will help quantify the eventual transformation of the cluster: cluster size and internal compactness (fractal dimension). 2.
This densification process, by the elimination of the larger pores without changing the internal cluster structure, allows synthesizing different kinds of porous glasses having strongly different physical properties, such as stiffness and mechanical properties, but also acoustical properties and permeability References [1] R.

The surface settlement is affected by many factors due to EPB shield.
The result indicates that soil warehouse pressure and the efficiency of grouting is important factors of the surface displacement.
In many factors about ground settlement caused by shield construction, the soil mass displacement of excavation face and back grouting of shield are two important factors.
Table 1 Mechanical and physical properties of soil strata soil layer unit weight [kN/m3] cohesion [kPa] angle of internal friction [°] elastic modulus [MPa] Poisson’s Ratio silty clay 1.82 19 20 16 0.33 residual soil 1.90 36.5 20.2 43 0.32 cohesive soil 1.92 36.5 20.2 40 0.32 fully weathered zone 1.96 39.4 22.7 79 0.32 strongly weathered zone 2.40 50 28 170 0.31 medium weathered zone 2.52 500 30 104 0.30 Analysis of Influencing Factors Soil warehouse pressure.
We can transform the unit type and mechanical parameters to simulate the equivalent layer.

This paper investigates the effect of heat treatment on the magnetic properties of nanocrystalline Fe-Ni-Si powders prepared by mechanical alloying method which can be used in soft magnetic composites fabrication.
These composites show similar magnetic, thermal and mechanical properties in three dimensions.
Magnetic, electrical and mechanical properties depend on preparation and fabrication processes, while purity, shape and particle size have an effect on all the properties [5].
Hence, magnetic properties will improve.
Shokrollahi; The magnetic and structural properties of the most important alloys of iron produced by mechanical alloying.

Other than magnetic particles surfactants (suspending agents, thixotropes), anticorrosion additives are important factors that affect the rheological properties, stability and redispersibility of the MR fluid [6,7].
On the basis of the stability tests were selected several fluids with the best properties for the study of magnetic field influence on the rheological properties of these sets.
Experimental fluid contains also surfactants: stearic acid ester and polyethylene glycol (PEG)Surfactants are important factors that affect the rheological properties and redispersibility of MR fluid.
The rheological properties of controllable fluids depend on concentration and density of particles, particle size and shape distribution, and properties of carrier liquid, additional additives, applied field.
The interdependency of all factors is very complex, yet is important in establishing methodologies to optimize the performance of these fluids for particular application.