Advanced Materials Research Vol. 744

Abstract: Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for predicting the lifetime for this type of alloy, particularly for low stress. This paper presents an analysis of the cavity nucleation, growth and coalescence mechanism of 9Cr-1Mo-VNb steel (P91 type) under high and low stress levels and multi-axial stress state.

Abstract: In this paper, we used the sol-gel method to get the green luminescent material precursors and prepared the Sr5(PO4)3Cl: Tb3+, Tm3+ green luminescent material by microwave-assisted sintering. Then we have studied the effects of different microwave time and power changes to samples structure and morphology, the effects of different halogen changes to samples structure and morphology, and the effects of different doping concentration and Halogen changing to luminescent properties. Using the X-ray diffractometer we study the samples crystal structure and survey the morphology and size by the scanning electron microscopy. Through the luminescent spectroscopy study the effects of Halogen changing. The results shows that: the optimum reaction conditions are microwave-assisted sinter at 800W for 60 min. Using F, Cl , Br three halogen prepared a halogen phosphate luminescent material, optimal luminous intensity are chlorine phosphate.

Abstract: In this paper we have successfully prepared the red luminescent material of La0.01Y1.99Sn2O7: Eu3+, Dy3+ by the method of hydrothermal and sintering. The phase structure, surface morphology and fluorescence properties were investigated by the scanning electronic microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). The EDS showed that the luminescent material is La0.01Y1.99Sn2O7: Eu3+, Dy3+. The SEM micrographs showed uniform particles with good crystallinity of luminescent material after sintering. PL spectrum showed the increasing of Eu3+ has great benefit for the increase of the luminous intensity of luminous materials. The optimal doping amount of Eu3+ ion and Dy3+ is 1:3 (nEu: nDy).

Abstract: An method for making AlN(aluminum nitride) nanowires by double decomposition, and the effection of additives was described. Future more, the growth mechanism of AlN nanowire synthesis with addictive were analyzed. AlN nanowire were synthesis by he AlCl3 and NaN3 in stainless steel cauldron without solvent and using Mg and Zn as additive. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study characters of the AlN nanowire. It is shown that the process can produce AlN nanowire with mean diameters ranging from 50 to 100 nm at 450°C. The additive has effective facilitated on the synthesis of aluminum nitride nanowires, can improve the properties of aluminum nitride nanowire, minish the average diameter of aluminum nitride nanowires.

Abstract: The effect of the graphite/epoxy composite patch parameters on the static and fatigue strength of the cracked aluminum plate was investigated experimentally. A series of specimens repaired by six types of composite patches including four different patch lengths and two different patch thicknesses were tested on the material tester. Specimens single-sided repaired and double-sided repaired by the same composite patches were also tested. The experiment results show that composite patches can provide an improvement in static and fatigue strength of the cracked aluminum plate, double-sided repair is more effective than single-sided repair, if the thickness and the length were selected properly, the composite patches can significantly enhance the strength of the repaired specimens.

Abstract: This thesis analyses the destruction mode, the crack developing and beam deflection changes of 20 reinforced concrete beams including un-strengthened beam, direct strengthened beam and secondary load reinforced beam through tests and researches. The results show that using CFRP to strengthen the reinforced concrete beams will not only effectively increase the bearing capacity of the beam, but also inhibit the beam cracking and improve the flexural rigidity of the beam during normal use. In addition, the initial damage will have a certain impact on the stiffness of the strengthened beam.

Abstract: The non-smooth surfaces on 45 steel were prepared by laser cladding with KF-300A alloy powder on the basis of the bionic non-smooth morphology of shark scales. The rib-type coatings were composed of hot-rolled steel 45 and clad layers containing hard phases such as WC/W₂C. In this paper, the influence of laser power and defocusing distance on the quality of cladding layer were investigated. The microstructure of the coatings was analyzed by scanning electron microscopy, with attached energy dispersive spectroscopy microprobe, and by X-ray diffraction. SEM inspection of the samples showed that all coatings exhibited similar phases in their microstructure, but the phases presented differ in morphology, size and distribution. Dilution and interaction zone of the coatings were also discussed in this paper. The results showed that the non-smooth coatings were crack-free and had a good metallurgical bonding with 45 steel trenches with a low dilution under the optimum laser conditions (P=700 W, f =14 mm, V=3 mm/s, continuous powder feeding voltage 2.1 V, nitrogen protection).

Abstract: In this paper, the restructured bamboo lumber was aged under three kinds of standards (ASTM D1037, BS EN 1087-1, WCAMA) to evaluate its weathering performance. The flexural properties, water absorption and thickness swelling of specimens were tested. The results showed that the retention rates of flexural properties were all more than 70% after three aging treatment. Simultaneously, the growth multiple of 24h water absorption was between 1.05 and 2.54, while those of 24h thickness swelling ranged from 0.06 to 0.38. It was suggested that restructured bamboo lumber could be utilized as outdoor structure material.

Abstract: This paper reported a validation of computational software system for creep damage analysis using circular notched bar. The complete computational software system for creep damage analysis consists of pre-and post-processing and the numerical solver and here the validation is primarily for the pre-and post-processing section developed by the authors. The creep damage evolution with time was post-processed interactively via FEMSYS.

Abstract: The beam member should not only meet the requirement of carrying capacity but also has the ability to resist deformation. The calculation of beam deflection mainly boils down to the stiffness calculation in the existing calculation theory of deformation capacity. The flexural stiffness of concrete beams after strengthened with CFRP has been improved greatly. Direct reinforcement and sustained load reinforcement short-term stiffness calculation methods of CFRP reinforced concrete in normal service stage are derived in this article, which could be used for strengthening design.