Key Engineering Materials Vol. 814

Abstract: Low-cycle fatigue test of three kinds of flat plates with different hole diameters (0.5 mm, 0.6 mm, 0.7 mm) and film-cooling hole arrangement (5 holes, 9 holes and 14 holes) were carried out. The variation of fatigue life with hole diameter and arrangement was analyzed. A modified critical distance method based on crystal plasticity theory was adopted to predict fatigue life under different hole diameters. The experimental results are as follows: the uneven distribution of stress was caused by the different arrangement of holes, which seriously affected the fatigue performance of the structure; the fatigue life decreased with the increase of the aperture. The critical distance method with the stress concentration factor around the aperture can accurately predict the fatigue life.

Abstract: Acrylonitrile-butadiene-styrene (ABS) was modified by aluminum oxide (AL₂O₃), talcum powder, kaolin and CaCO₃. ABS samples were printed by 3D printer after the ABS silk was made. Then the mechanical properties, morphology, melt flow rate were studied in this article. AL₂O₃ has the best enhancement effect on ABS than other particles, and the melt flow rate was improved when content of AL₂O₃ less than 10%.

Abstract: Through a series of mechanical properties tests and microstructure observation, the effects of artificial heat treatment (AA), pre-stretching aging (PA) and pre-stretching creep aging (PCA) treatment on the precipitation phase type and mechanical properties of X2A66 aluminum-lithium alloy were studied. The results show that compared with AA, PA treatment promotes the uniform precipitation of high-density T₁ phase, so that the yield strength, tensile strength and elongation of the alloy reach 593.4Mpa, 610.8Mpa, 10.7%. Further, the creep aging treatment on the basis of the pre-deformation can further increase the strength (613.6Mpa, 628.9Mpa) of the alloy with a slight decrease in the elongation (10.3%).

Abstract: In the present work, the effects of pre-deformation before aging on the precipitation phase and mechanical properties of a new type X2A66 alloy was investigated with the help of the room temperature tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The experimental research results prove that reducing the aging temperature or pre-deformation before aging is beneficial to improve the mechanical properties of the alloy. Compared with decreased aging temperature, pre-deformation treatment before aging can significantly improve the mechanical properties of the alloy, and its yield strength (YS), ultimate tensile strength (UTS) and elongation are 593.4Mpa, 610.8Mpa, and 10.7%, respectively.

Abstract: Aiming at the damage and failure problem of copper alloy netting structure, the ultimate strength and fatigue performance of the net structure were studied by test method. Based on the research on the ultimate strength of copper wire, through a series of fatigue tests on copper wire and net structure, the fatigue life and failure modes of copper wire and net structure under different loads are analyzed, and their fatigue life curves are also drawn. The results show that the fatigue strength of copper wire and net structure considering corner processing is lower than that of copper wire not considering corner processing, which indicates that corner processing has a great influence on the fatigue strength of actual copper net structure. Compared with the fatigue strength value of 32.8 MPa of the copper net, the fatigue strength value of the net structure decreases to a certain extent (about 14.3%), which indicates that the assembly process of the copper net has certain influence on the fatigue life of the net structure.

Abstract: Quick dry inner wear products become increasingly popular in the tropical regions with a hot and rainy climate. This study evaluated the quick dry property of three inner wear for women available in the market via studying their wicking rates. It was found that one products had satisfactory wicking ability as they claimed, whereas one products showed no quick dry property.

Abstract: Gauze is an excellent material for infant apparel which can made in various forms and by a variety of methods, and thus have attracted great attention in baby care market. This study aims to identify the wicking property of the gauze fabric in baby care products, and to analyse the relationships between the wicking ability and fabric structure of baby soft gauze products. The experimental results revealed that a significant difference occurred for the gauze in the wicking ability. The cotton gauzes were found to show higher wicking rate than bamboo counterparts because of the higher hydrophilic property of cotton material. The fiber content and structure of fabric were the major parameters that affects the wicking ability.

Abstract: In order to protect the oil&gas reservoirs, a surfactant vinyl cationic clay (Na-MMT) anti-swelling agent diethyl dodecyl allyl ammonium chloride (DDAAC) was prepared from diethylamine, chlorododecane and allyl chloride as raw materials. The single-factor orthogonal test was used to determine the optimal synthesis scheme for DDAAC: reaction temperature 40 °C; reaction time 4 h; pH= 9; n (diethylamine): n(chlorododecane): n(allyl chloride) = 1.1:1.0:1.8. The experimental results showed that the anti-expansion rate of 0.5wt% DDAAC can reach to 78.31%. FT-IR were utilized to study its anti-expansion mechanism, and FT-IR showed that physicochemical adsorption between DDAAC and Na-MMT occurs.

Abstract: Microstructure damage and evolution in 4H-SiC under He-ion implantation and post-annealing have been investigated by the combination of fourier transform infrared spectrometer (FTIR), Raman scattering spectroscopy and high resolution X-ray diffractometer (HRXRD). After implantation, the 4H-SiC specimen exhibits a heavy damage and some amorphous state appear. With increasing annealing temperature, to some extent recovery in damaged lattices was observed, as a result of the peaks of Raman and HRXRD regain their intensities. However, the reverse annealing behavior in damaged peaks was displayed after annealed at 973K. This reverse annealing effect was revealed to be due to the formation and the growth of He bubbles above 973K.

Abstract: A novel thermal management system (TMS) for Li-ion battery module using phase change material (PCM) and cooling water as the heat dissipation source to control battery temperature rise has been developed. Graphite sheets were applied to compensate low thermal conductivity of battery and PCM and improve temperature uniformity of the batteries. One discharge (1C rate)-charge (2C rate) circle was applied in battery modules to test the effectiveness of this TMS. A three dimensional numerical model of the battery module with the TMS was conducted. The results show that this TMS basically meets the demand about the maximum temperature difference of battery module and totally keeps the maximum temperature within the optimum operating temperature range (≤45°C).