Applied Mechanics, Materials and Manufacturing IV

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Authors: Qi Wei Zhu, Mei Gui Ou
Abstract: PEG (polyethylene glycol) have been widely used in the synthesis of nanomaterials due to its special structure and performance. In this paper, the role PEG played in the preparation of nanomaterials, such as dispersion and stabilization, structure-directing, modification and functionalization were summarized.
Authors: Hui Qu, Shi Quan Liu
Abstract: Different ways to prepare nanosized nickel ferrite particles have been developed. Typical solid state reaction routes including high temperature sintering, mechanical alloying, self-propagating high temperature synthesis and wet chemistry methods including co-precipitation, sol-gel, hydrothermal synthesis are briefly reviewed and compared by focusing on the particle size control.
Authors: Wei Tai Huang, Der Ho Wu, Shih Pin Lin, Jian Ting Chen
Abstract: This objective of this article is to present a new technique of nanofluids/MQL in high speed milling by using MWCNTs. In the past, studies have shown the MQL process can improve tool life and surface accuracy in high speed cutting. The purpose of using carbon nanotubes is to increase the thermal conductivity of cutting fluid and to reduce the temperature during the cutting and decrease the thermal wear of tool. The proposed study is to investigate the characterization of the MWCNTs/ nanofluids combined with MQL during the high speed milling of AISI 1050 and AISI P21 experimentally. The Taguchi robust design was also used to optimize the parameters of nozzle with respect to tool feed direction, such as spraying distance, angle of ejection, and relative locations for improving the MWCNTs/MQL cutting effect. Experimental results showed the MWCNTs/ nanofluid had the benefits of improving surface roughness and reducing wear of tool in high speed milling. The results were compared to dry cutting, and wet cutting in detail.
Authors: Sui Yuan Chen, Jin Huan Wang, Xian Zhou, Jing Liang, Chang Sheng Liu
Abstract: The targets are micron-sized TiO2 powders and micron-sized Ag powders, TiO2@Ag nanocomposite particles with core-shell structure were synthesized by pulsed laser gas phase evaporation-liquid phase collecting method. The morphology, structure and synthesis mechanism of the samples were studied by means of transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), and X-ray diffraction technique (XRD). The results show that the pure TiO2 nanoparticles sol was firstly prepared as liquid phase collecting system using gas phase evaporation-liquid phase collecting method; then, the target was changed using Ag, and TiO2 @ Ag nanocomposite particles with core-shell structure, which are spherical or ellipsoidal, were successfully synthesized under certain conditions of laser synthesis parameters; the diameters of most TiO2@Ag nanocomposite particles covering synthesized after 2h range from 15nm to 35nm, the diameters of most TiO2 @Ag nanocomposite particles covering synthesized after 4h range from 25nm to 50nm, and the size of nanocomposite particles increases with the increase of covering synthesis time; TiO2 nanoparticles synthesized previously in liquid phase function as crystallized cores, while Ag atoms and their clusters are adsorbed to TiO2 surfaces and surround the surfaces to form TiO2 @ Ag nanocomposite particles.
Authors: Zhi Long Pan, Shi Liang Ao, Jian Ping Jia
Abstract: Oxide free Tin nanoparticles were synthesized from a chemical reduction method. Their morphological and thermal characterizations were studied in this paper. The X-ray diffraction (XRD) study showed that no oxides of Tin nanoparticles were formed. The thermal characterization by differential scanning calorimetry (DSC) exhibited the size dependency of the melting points. The melting point was as low as 202.16°C.
Authors: Horng Yu Wu, Ming Chieh Lin, Feng Jun Zhu, Cheng Tao Wu, Ching Hao Liao, Chui Hung Chiu
Abstract: The flow behavior and associated microstructural changes of wrought 6069 Al alloy deformed in tension were analyzed in this work. Tensile tests were conducted on an extruded tube with a thickness of 1.6 mm in the temperature range of 300–500 oC, with initial strain rates from 0.001 to 0.1 s-1. The true stress–true strain curves exhibited a peak stress at a critical strain. The overall level of the flow curve increased when the strain rate was increased and/or the temperature was decreased. The flow curves exhibited a typical flow behavior with dynamic softening and showed that the softening degree after reaching the peak stress was dependent on the deformation conditions. This could be related to the softening mechanism. The main softening mechanism of the alloy was dynamic recovery (DRV) at low temperatures; dynamic recrystallization (DRX) occurred as deformed at high temperatures.
Authors: Shi Dong Wang, Qiang Wang, Jing Li, Shu Liang Zang
Abstract: This paper uses a metal hung weight loss method, acidic ionic liquid desulfurizer as the media, by adding different inhibitor (Polyethylene Glycol, SDBS, Functional ionic liquids), contrast to carbon steel corrosion in the absence of inhibitor, understanding of their respective inhibition effect. In the experiment, the carbon steel material, different kinds and concentrations of the inhibitor in the medium, the corrosion rate measured by weight loss method. Contrast to the blank experiment the inhibition rate can be calculated. The experiment proved that the inhibition effect of several inhibitor at room temperature, and calculate their respective optimal concentration. The experiment also investigated the compound of several corrosion inhibition synergies, confirm the good corrosion inhibiting effect of polyethylene Glycol and SDBS complex, the inhibition rate reached 69.2%.Excellent inhibition effect of the ionic liquid corrosion inhibitor and the inhibition rate reached 88.3%, showing a clear advantage.
Authors: Ming Hua Wu, Zhan Ying Liu, Hui Yang
Abstract: In bar rolling of S31803 duplex stainless steel, the surface crack is easy to appear. Through the observation on the microstructure, ferrite and austenite morphology and phase ratio were analyzed. The surface cracks of S31803 duplex stainless steel bar is mainly because of the dual phase microstructure softening mechanism of different in thermal processing, and the double phase stainless steel heat plasticity decrease. When the ferrite and austenite proportion close, and the heating temperature is too high, to reduce the binding force between the grains of billet surface, easy to cause the crack surface of a bar.
Authors: Xiao Jun Shen, Cheng Wang, Dong Sun, Zhi Lin Lai, Dong Ye Yao
Abstract: For comparative study of the influence of laser shock peening and ultrasonic shot peening on the mechanical property of superalloy K403, untreated, ultrasonic shot peening with 850°C heat preservation, laser shock (heat preservation, Hp), the fatigue testing of samples under four states were conducted at room temperature, and the analysis of two techniques’ influence on the mechanical properties of K403 was done by hardness tester, profile tester, scanning electron microscopy (SEM). The results indicated that LSP with Hp, LSP, USP with Hp can improve the fatigue life of K403 respectively for 2.4, 2.25, 1.4 times more longer than untreated sample; the increase of micro-hardness gradient after LSP were smaller than after USP. The SEM studies showed that the γ' phase distortion was elongated and the plastic deformation of samples by LSP was larger than by USP.

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