Applied Mechanics and Materials Vol. 487

Abstract: The structure and properties of the Ti-Al composite electrode materials prepared by the anti-gravity casting method was analyzed by SEM, EDS, four-probe method and electrochemical workstation. The results show that the metallurgical bonding of Ti and Al can be achieved by the method of anti-gravity casting with the Al temperature800°C, mold temperature of 400°C, pressure difference 0.5MPa. The electrochemical properties of the composite electrode materials is much better than pure Ti anode. Under the same condition,polarization potential of composite materials will fell by 32mV~43mV in polarization potential of pure Ti, it can be increased by 60% or more in current density, the resistivity was only 1/10 of pure Ti.

Abstract: An experimental system of Fe₃O₄-H₂O nanofluids on convective heat transfer characteristics was presented. The influences of magnetic field direction and intensity, particle mass fraction, axial distance were presentd. The experimental results show that the synergic function between the external magnetic field and the thermal field has impact on convective heat transfer characteristics of the device.

Abstract: 304 stainless steel and 316L stainless steel are conventional materials of primary pipeline in nuclear power plants. The present work is to summarize the acoustic emission (AE) characteristics in the process of pitting corrosion of 304 stainless steel, intergranular corrosion of 316L stainless steel and weldments of 316L stainless steel. The work also discussed the current shortcomings and problems of research. At last we proposed the coming possible research topics and directions.

Abstract: In this paper, we produced the 0-3 PZT/P(VDF-TFE) piezoelectric composite film with 80μm thickness using PZT piezoelectric ceramics and fluorine resin P(VDF-TFE) by weight 85/15 ingredients through the hot rolling machine and corona-discharge method. A sensor with 4cm×1.3cm area is designed and produced by using this film. We have carried out the breaking of a pencil lead pressed against an aluminum plate acoustic emission testing. The result shown that the sensor is with fast response and high sensitivity advantage, the sensor can be used as acoustic emission sensor. Meanwhile the sensor is very easy to use due to it is a soft film sensor.

Abstract: Based on the nonequilibrium Molecular Dynamics method, interfacial thermal resistances of Si/3C-SiC/grphene composite films are investigated. The dependencies of interfacial thermal resistances of Si/3C-SiC and 3C-SiC/grphene on temperatures and the thickness of buffer layers are simulated separately. The results indicate that the interfacial thermal resistances of Si/3C-SiC and 3C-SiC/grphene increase with the increase of temperatures at the range of 100~700K, and converge to 3.4×10-9 Km²/W. In the Si/3C-SiC/grphene composite film, 3C-SiC connects Si substrate with grphene sheets. The results show the relationships between interfacial thermal resistances and the thickness are not prominent, and the maximum value of interfacial thermal resistance locates at 24×3.35 Å.

Abstract: ZrN thin films were successfully deposited by DC magnetron sputtering on die steel substrates. The objective of this study was to investigate heat treatment on the microstructure, morphology, nanohardness properties determined by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), nanoindentation, and pin-on-disk, respectively. The XRD result shows that ZrN has intensity of (111) and (200) peak after 400 °C for 1 h at lower nitrogen flow rates. The surface of coatings revealed smaller grains and smooth surface under heat treatment. ZrN coatings consisted of lower nitrogen flow rate had much lower friction coefficient, better mechanical properties by annealing treatment process.

Abstract: Aluminium metallization has a disadvantage when it comes to high-end applications as it cannot withstand the high temperature and pressure. This paper studies the factors that affect the surface roughness on a Platinum deposited wafer after reactive ion etching (RIE) using a combination of CF₄ and Argon gaseous. A total of three controllable process variables, with 8 sets of experiments were scrutinized using a systematically designed design of experiment (DOE). The three variables in the investigation are ICP power, Bias power, and working pressure. The estimate of the effect calculated for ICP power, Bias power, and working pressure are-6.3608, -3.2858, and-5.394 respectively. All three factors gave negative effects. This implies that the surface roughness decreases when ICP power, Bias power, and working pressure is high. The ICP Power is the most influential factor followed by working pressure, and bias power.

Abstract: Objective: The aim of this study was to evaluate the adhesion of Streptococcus mutans (S. mutans) on different types of orthodontic elastic O-rings.

Abstract: In this paper, Ni-Co coatings on Al foil were prepared by electroplating to obtain Al/Ni-Co composite. Phase transformations and magnetic property of Al/Ni-Co composite heated at 823 K for 80 h were investigated. The results showed that obviously exchanged zone in Al matrix exited and the thickness was about 2.5μm. Ni diffused into the Al easilier than Co. β phase (AlNi and AlCo) and γ phase (Al (Ni, Co) solid solution) of Co-Ni-Al formed during the annealing. The Ms of was decreased significantly when Al diffused into the NiCo alloy film and formed Ni-Al and Co-Al intermetallic compounds.

Abstract: To study the effect of recycled coarse aggregate, water-cement ratio and mixture ratio on the physico-mechanical properties of recycled concrete, determine the finial optimum mixture ratio and physico-mechanical properties of recycled concrete with the optimum mixture ratio, physico-mechanical tests are done on recycled concrete and conventional concrete. Results show that with the replacement rate increasing of recycled coarse aggregate, the compressive strength and splitting tensile strength of recycled concrete increase and then decrease. It is feasible to develop the concrete with 100% replacement rate of recycled coarse aggregate. With an increase of recycled coarse aggregate replacement rate, dry shrinkage ratio of concrete increases gradually, but the increasing range has little effect on the concrete. The concrete strength of 28 days is linear with water-cement ratio with the correlation coefficient is 0.98763. Taking appropriate mix design, the physico-mechanical properties of recycled concrete will surpass or be equivalent to those of conventional concrete. Recycled concrete of the optimum mixing rate is the high strength with lower brittleness.