Advanced Materials Research Vols. 750-752

Abstract: In this paper, MgO with different contents was coated on the surface of magnesium borate whisker using chemical precipitation method. The resistance to compression of whisker perform was measured, and the effect of MgO coating on the deformation resistance of magnesium borate whisker perform was studied. The result shows that the compression strength of whisker perform sintered at 900°C was enhanced with increasing MgO coating ratio to magnesium borate whisker. The compression strength was increased from 0.80MPa for coating ratio of 0 to 1.34Mpa for coating ratio of 1:10. Then magnesium borate whisker-reinforced pure aluminum (MBOw/Al) composite without apparent microscopic defects was fabricated using modified whisker perform. The tensile strength and elastic modulus at room temperature attain 240MPa and 130GPa, respectively.

Abstract: Obvious physical process differences exist between overlapping area and non-overlapping area by broad-beam laser cladding,also the parallel and vertical interface of RP.By comparing the microstructure and performance, the result shows: the microstructure of overlapping area has broken crystal,the size of overlapping area crystal is bigger than the non-overlapping one.Repeated heating makes overlapping area secondary dissolving out and having higher rigidity;Between layer and layer of broad-beam laser cladding RP is metallurgical combination completely,the degree of uniformity of central microstructures performance is good,hardness of the bow shape area between overlapping layer and matrix is greatly increased.

Abstract: Gather is one form of pleat, and it is a typical form in decoration of apparel. Gather has certain shrinkage degree and shrinkage is relevant with the fabric property. In order to design perfect form of gather, the relationship between all fabric properties (thickness, drape coefficient, surface density, flexural rigidity, and density) and shrinkage should be worked out. In this paper, the fabric properties and shrinkage were obtained via experiments. And then, the data was analyzed by SPSS statistical software to get the mathematical relation between the fabric properties and shrinkage. The mathematical model of calculating shrinkage using surface density was deduced and validated through practical application.

Abstract: Shendong mining area hanging nets adopted metal mesh material in the traditional through of fully mechanized coal face. Whose defects were the high cost of materials, process cumbersome, great labor intensity and time consuming. Therefore, new high-strength polyester fiber flexible mesh material was introduced. Its main advantages are: light weight, tensile resistance and drag force strong, flame-retardant and anti-static, low cost, simple process, high efficiency, coal cutting speed. The construction technology process in detail were designed which contained flexible network transported, fixed, dropped and raised. The project was implemented in Shigetai Coal at the end of No.12401 mining face. Results show that from working face mounting network to smoothly through with only 40 hours, compared with the traditional metal net can save 44 hours and cost 480000 yuan.

Abstract: Vehicle engineering materials are used in manufacturing of vehicle. Its status quo and development trend are analyzed. Proportion of steel in structure material will reduce stage by stage. With reliable performance, steel will be replaced by light and new-style materials such as aluminous alloy, compound materials. Plentiful developing rapidly new materials, such as macromolecule materials, compound materials, offer necessary condition to develop vehicle.

Abstract: In this paper, the friction and wear behavior of FKM, NBR and FKM/NBR blends with the same Shore hardness was investigated in the MPV - 600 wear tester under water lubrication based on the actual working parameters of the screw pump. Wear mechanism of FKM/NBR blends with different load was also analyzed according to their wear loss and frictional coefficient. The results showed that the wear resistance of NBR was improved by the addition FKM. FKM/NBR blend with ratio of 2:8 owned the optimal wear resistance, which was close to that of FKM. The wear of FKM and FKM/NBR blend with ratio of 2:8 was controlled by fatigue wear, and the others were mainly controlled by abrasive wear.

Abstract: Detonation pressure profiles in TNT/RDX and its mixtures with aluminum powders of different particle size have been studied with Manganin piezoresistance gauge. The measured detonation pressure accorded with the calculated detonation pressure. The results show that micrometer aluminum powders reacted with detonation at times of 0.5μs after the peak pressure. Aluminum powders did not react in the detonation zone, and introducing aluminum into explosive would reduce the detonation pressure. Compare with micrometer aluminum powders, nanometer aluminum powders reacted with detonation product more quickly.

Abstract: Failure reason of boiler extraction steam pipe was discussed by means of macro-observation, chemical composition analysis, metallurgical and SEM microstructure examination and EDS analysis. Results showed that the crack initiated from original corrosion flaw on outer wall of the extraction pipe, propagated rapidly under large pressure caused by water-hammer due to no drainage design in the unit pipe system until final bursting.

Abstract: The hot compression tests on a Gleeble-1500D thermal mechanics simulator were carried out under the strain rate range of 1~ 0.005s-1 at the temperature range of 873-1373K in order to evaluate the constitutive equation of 5Cr21Mn9Ni4N valve steel. All of the flow stress curves exhibit a single peak stress, after which the stress is followed by a steady state regime. The results indicate that the deforming behavior is strongly depending on the strain rate and the deforming temperature. According the experimental data, the hyperbolic law is used to develop the constitutive equations. In the constitutive equations, the effect of the deforming temperature and the strain rate are represented by the Zener-Hollomam parameter. And the flow stress curves are coinciding with the constitutive equation of .

Abstract: By macro and micro morphology observations, chemical analysis, metallurgical observations, SEM observations and EDS analysis, the failure cause of a colored steel plate used as the workshop roof in a plant was analyzed; then, some improved measures were also proposed in this paper. It is demonstrated that failure of the colored plate is caused by the synergism of high temperature, and sulfur dioxide corrosion. The high concentration sulfur dioxide of the local area on the colored plate is the main failure cause.