Applied Mechanics and Materials Vol. 441

Abstract: In the present study, Fe-50at%Al/WC intermetallic matrix composite powder was produced through mechanical alloying (MA) followed by annealing treatment. The phase transformations, grain size, microstructure and thermal stability of the composite powder during milling and annealing treatment were studied. The results showed that a bcc Fe(Al) solid solution reinforced with nanoscale WC particles was formed through high-energy ball milling The grain size of Fe(Al) decreased and the lattice strain of Fe(Al) increased with increasing milling time. The as-milled Fe(Al)/WC composite powder had lamellar structure. The oxygen content of Fe(Al)/WC composite powder increased with increasing milling time. The phase transformation from Fe(Al) to Fe-Al intermetallic phases was related to the milling time of composite powder and could occure at temperature of 400°C.

Abstract: This study investigates the optimization of micro milling EDM process parameters to achieve multiple performance characteristics (low electrode depletion (ED), high material removal rate (MRR) and low overcut) in the Inconel 718 by the Grey-Taguchi method. Experimental results show that the electrode depletion decreased from 0.56 to 0.52 10^-8 mm³/min, the material removal rate increased from 0.47 to 1.68 10^-8 mm³/min and the overcut decreased from 1.27 to 1.19 μm under optimal micro milling EDM process parameters. Furthermore, control charts tell us when special causes of variation are impacting machining process. Control charts are basic and powerful tools in statistical process control and are widely used to control various industrial processes. The aim of statistical process control is to explore the predictability of a process. It was found that the EDM process and product characteristics are stable over time.

Abstract: In this paper, Al-doped ZnO thin films were deposited on glass substrates by RF magnetron sputtering and subsequently rapid thermal processing was executed under temperature range from 300°C to 600°C in order to investigate the microstructure, electrical, and optical properties of AZO films. XRD and AFM microscopy results showed that all the samples were of poly-crystalline and the grain size became larger with the increasing processing temperature. Compared with the sample as-deposited, it was shown that resistivity decreased from 1.9×10^-2 to 1.48×10^-3Ωcm and carrier concentration increased from 1.48×10²⁰ to 5.59×10²⁰ cm³ when the sample was processed at 600°C in pure nitrogen for 1 min. The highest transmittance of the samples processed at 500°C improves to 90.35% compared with the as-deposited films (68.2% ) as the wavelength varied between 400 and 900 nm.

Abstract: The diamond impregnated bit matrix should not only wrap the diamond up firmly; also constantly wear in the drilling process to ensure that the diamond can be made exposure constantly. The wear of diamond impregnated bit matrix is the key to affect the exposure of diamond blade.In this paper, based on the tribology, the wear mechanism of drill bits matrix is analysed from the microscopic view.Then,the relationship between matrix hardness and abrasion resistance can be obtained.

Abstract: This work summarizes the interfacial reaction between lead-free solder Sn-3.5Ag and electrolessly plated Ni-P metallization in terms of morphology and growth kinetics of the intermetallic compounds (IMC). Comparison with pure Ni metallization is made in order to clarify the role of P in the solder reaction. During reflow, the IMCs formed with the Ni-P under-bump metallization (UBM) exist in chunky crystal blocks and small crystal agglomerates, while the ones with the sputtered Ni UBM exhibit uniformly scallop grains with faceted surfaces. The IMC thickness increases with reflow time following approximately a t^sup 1/3^ power law for both systems. The IMC growth rate is higher with the Ni-P UBM than the Ni UBM. The thickness of the Ni^sub 3^Sn^sub 4^ layer increases linearly with the square root of thermal aging time, indicating that the growth of the IMCs is a diffusion-controlled process. The activation energy for Ni^sub 3^Sn^sub 4^ growth in solid-state reaction is found to be 110 kJ/mol and 91 kJ/mol for the Ni-P and sputtered Ni UBMs, respectively. Kirkendall voids are detected inside the Ni^sub 3^P layer in the Sn-3.5AgTNi-P system. No such voids are found in the Sn-3.5AgTNi system.

Abstract: Key parts of pump produces belong to the thin-walled parts.And cutting parameters have a direct influence on the processing accuracy of impeller. To solve this problem, it is necessary to found the simulation model of tool and workpiece based on advanced metal cutting simulation software named Advant Edge FEM. And stress load should be loaded, using single factor analysis method to study the law of influence and its causes of the milling cutting parameters on pump thin-walled parts cutting force. And the gotten results can provide reference for the design and manufacture of pump thin-walled parts.

Abstract: The technology monitoring the operating state of the architecture construction is always hot topics in civil engineering. In this paper, attempts using the NiTiSMA film/ferroelectric ceramics PZT composite materials with the function of force - electricity conversion are introduced to the design of structural safety monitoring system. The sensing materials based on the function of force - electricity conversion, directly perceive the stress changes of architectural structure under the vibration loads, monitoring the state changes of internal cracks in the architectural structure. The results show that the safety monitoring system of architectural beam structure,on the sense of NiTiSMA film / ferroelectric ceramics PZT composite materials, possesses reaction speed in milliseconds, response frequency at 0-1000 Hz. It is suitable for monitoring the damage status of cracks in the architecture construction.

Abstract: In order to determining technological parameters and effective range of vibratory stress relief (VSR) treating for the radial steel gate structure, kinetic analysis was carried out according to the industrial standard. The natural frequency, vibration mode and the curves of amplitude-frequency were obtained by using Finite Element Analysis (FEA),which gave some suggestions for reference on how to determine the technological parameters for large-sized welding structures.

Abstract: The electrode material plays a very important role in the electric discharge machining, affects the electrical discharge machining efficiency and machining surface quality. Experiment testing and materials analysis as the primary method, affect layer thickness and workpiece surface roughness value as evaluation indexes. PCD cutting tool samples were electrical discharge machined using copper electrodes and graphite electrodes respectively. After machining, the PCD cutting tool samples' surfaces were analyzed by X ray diffraction, the surfaces appearances were observed under the scanning electron microscope, and the surface roughness values were measured by roughness measuring instrument. PCD samples' surface effect layer thickness values and surface roughness values, affect layer distribution structure was statically analyzed in typical EDM process conditions with different electrode materials. Summary electrode material effect on PCD cutting tools in EDM processing. Provides an important experimental basis for designing technics of precision and highly efficient electrical discharge machining PCD cutting tools.