Advanced Materials Research Vols. 123-125

Abstract: Reversible and irreversible events can be resolved) using modulated temperature DSC and TMA. Each technique has advantages, those for TMA include longer times and slower scan rates that allow greater approach to material equilibrium. The thermal expansion coefficient and glass transition temperature can be isolated from relaxations and structural changes. Modulated temperature thermomechanometry (mT-TM) is used to characterize amorphous thermoplastics including PS, PMMA, PC and PPO, and the results including annealing, heating and cooling.

Abstract: Delamination is one of the most common modes of defects of laminated composite shell roofs. A review of literature that exists on composite shells reveals that the research reports on delaminated shells are very few in numbers. Present paper deals with the static analysis of delaminated composite conoidal shells with simply supported boundary condition and subjected to centrally applied point load. For the present study work a finite element approach using eight noded isoparametric shell element with five degrees of freedom per node is employed. A multipoint constraint algorithm is incorporated, to satisfy compatibility of deformation and equilibrium of forces and moments, which leads to unsymmetrical stiffness matrix. This formulation is validated through solutions of benchmark problems. Lamination and extent of delamination area are varied to compare the performances of delaminated conoidal shells against those with no damage. Based on the present comparison some engineering conclusions are also included in this paper, which will serve as future reference.

Abstract: Combustion gas of gas turbine is about 1100 ~ 1300 °C. Is doing TBC(Thermal Barrier Coating) on the base metal surface to protect rotor or blade from high temperature flame. TBC system reduced heat transfer as metal base metal. TBC system is divided by bond coating of prevent oxidation and corrosion and Top coating reduced of heat transfer by high Temperature flame. The objective of this study was to development of an advance TBC system for high Temperature (>1350°C) gas turbine components. Used coating powder developed newly in coating process, and more than 1350°C by parameter control in usable coating method develop. Internal studies looked at the effect of TBC coating thickness, material chemistry, substrate composition, surface temperature and bond coat as-sprayed surface profile/particle size on technical performance.

Abstract: In the present study, the effects of forging or ring-mill processing on the tensile properties of B7B4 were investigated. Tensile specimens were fabricated including centrifugal casting (Case 1), centrifugal casting + forging (Case 2), and centrifugal casting + ring-mill (Case 3). Tensile tests were performed at room temperature. An optical microscope and a scanning electron microscope (SEM) were used to examine the changes in the microstructures of the specimens prepared by the three processes. The results showed that the moduli of elasticity and yield stresses of B7B4 prepared by the three processes had no much difference. The elongations of Case 2 and Case 3 were 30% higher than that of Case 1. SEM images revealed that the orientation and fine structure were affected by the forging and ring-mill processes.

Abstract: Applied gas turbine blade material(Ni base Super-alloy) for aircraft as principal parts material of existing electricity generating gas turbine blade. Studied microstructure change after do heat treatment, Hot Isostatic Press(HIP) processing to nickel-based super-alloy. Emphasize in properties of matter refreshing effect confirmation by HIP processing, microstructure observed by scanning electron microscope. HIP processing effect caused positive effect in high temperature Creep and low cycle fatigue failure by microscopic air hole exclusion. Sheep of Eutectic region decreased solid solution being done B, and also precipitated size of cuboidal shape great. Heat treatment effect was seen modification by M23C6 carbide creation that Script MC carbide is microscopic and does Discrete through solution treatment in high temperature state. Precipitation that grow after HIP processing over solution processing and aging processing in heat treatment process solid solution after is done again precipitate being done size decrescent.

Abstract: This study designed a flexible electromagnetic resistant fabric it is not only apt to make protective clothing, but also simple process dependence on its application. Polylactide fiber (PLA) and the low melting polylactide fiber (LMPLA) were blended to fabricate nonwoven matrix. Then polyester (PET) aluminum foil inserted between two layers of PLA nonwoven matrix to fabricate a compound matrix by needle punching. Afterward, physical properties and electromagnetic shielding effectiveness of different layers compound matrix were be evaluated.The result indicated that Tensile strength of sample B was 189.16 N; tear strength of sample C was 579.43 N. Burst strength of sample B which was laminated five-layers compound matrix had best burst strength, 3326.18 N, and excellent electromagnetic shielding effectiveness, over 90 dB.

Abstract: In this research, we used the special needle punching process to improve the disadvantages of the ordinary needle punching process. First, we manufactured the single-layer needle punching nonwoven by the ordinary needle punching process and then nonwovens were laminated followed by needle punching. We carried on this manufacturing processing until the multiple needle-punching nonwoven reached the certain thickness and area weight which were both limited in the ordinary needle punching process. The combination of two manufacture techniques as multiple thermal bonding and multiple needle-punching freed the single needle-punching from the limit of the expected thickness and area density. In this research, we tested the mechanical properties and sound absorption of the multi-layer needle-punching nonwoven and multi-layer thermal bonding nonwoven. According to the results, the tensile strength is higher than the multi-layer thermal bonding nonwoven; however, there was no distinct difference between the multi-layer needle-punching nonwoven and multi-layer thermal bonding nonwoven on the sound absorption performance.

Abstract: The effectiveness of residual stress on forming copper patterns of printed circuit board was investigated during applied thermal conditions. Generally, the electrolytic copper foil showed a compressive residual stress about -55~-60MPa as received, which easily caused to form copper patterns irregularly when the pattern was etched finely. The compressive residual stress was relaxed with applying heat-treatment for a few hours. However, we observed that the compressed residual stress of copper foil tended to be relaxed, constant, and compressed again during heat-treatment process, which is mainly considered as that the grain of copper is grown restrictively within a Cu thin foil layer. We suggested a quantitative method for controlling grain size, grain distribution and relaxing stress of copper foil, which was very helpful for increasing an etching factor to decrease pattern width.

Abstract: Recently, semi-solid processing is paid to attention in the field of the light alloys. By this method, it is improved ductility and fatigue strength. Although, because of those mechanical properties of the elongation and toughness is not excellent, the range that can be the application to parts is limited. On the other hand, it is reported that grain refinements cause improvement of ductility and appearance of super plasticity. Then, Equal-Channel Angular Pressing (ECAP) method is reported to be effective to the sample making of a bulk and ultra fine grain in various alloys in recent years. In this study, it tried to improve ductility and durability due to making ultra fine grain in AC4CH alloys by the ECAP method, and the influence of ECAP processing on the mechanical property of AC4CH was investigated. As the result, the ductility of AC4CH has improved by ECAP processing. However, the tensile strength of AC4CH declined along with the increase in the number of passes. So, for the purpose of additional improvement of tensile strength, ECAP-Back Pressure (ECAP-BP) method that was reported to be more effective for grain refinements than ECAP method was applied to semi-solid AC4CH and compared with ECAP method. As the result, the tensile strength of AC4CH was maintained by use of ECAP-BP. Moreover, both ductility and toughness of that have been also improved.

Abstract: The temporary filling material seals up the tooth cavity so as to prevent bacterial leakage and the second infection in the root-end treatment. Chitosan is biodegradable, bio-resorbable, non-toxic, and antibiotic. In this study, chitosan fiber is used to enhance the temporary filling material compressive strength and the tooth bite force. IRM® is reinforced by the 2, 4 and 6 wt% chitosan fibers, respectively. And after solidified the IRM®/ Chitosan fiber composite temporary filling material was obtained. Then setting time, solution test, compressive strength and dye micro-leakage of IRM®/ Chitosan fiber composite temporary filling material were be evaluated. In result, maximum compressive strength of IRM®/ Chitosan fiber composite temporary filling material was obviously increased 200 N than IRM® matrix. As to the micro-leakage test, no trace of leakage was found on the 7th day. Consequently, IRM®/ Chitosan fiber composite temporary filling material can be a good candidate in the short-term dental clinical surgery.