Applied Mechanics and Materials Vol. 442

Abstract: After a Hastelloy C-276 cylindrical part goes through the power spinning process, X-ray detection, and tensile and corrosion tests, the directivity of grains in the cylindrical part is enhanced, and the weld zone strength and post-annealing corrosion resistance greatly promoted.

Abstract: The paper is focused on study of cladded layer properties created by laser beam, to abrasive wear resistant. As a basic material was used alloyed tool steel X37CrMoV5, the layers wascreated by laser beam by using a filler materials in the form of wire PZ 6159 and PZ 6168. The aim is research ofcladded layers structures changes, theirmicrohardness changes relative to the basic material and determine the abrasive wear resistance. One of the most important advantages of laser cladding technology is bringing the wire to the exact place of the interaction of a laser beam.

Abstract: Dust particles from the air in the electrical contact caused more and more problems. To a large extent reduce the reliability of the system. In order to study the impact of these issues, we need to analyze and discuss the dust particles on contact performance of electrical contact materials. In this paper, under static conditions with 70-150μm of the silica particles analyzed and discussed, represented by the pressure difference, particle size, being suppressed will lead to a different location of the static contact resistance and analysis of particle size of the scope of what the content of easily crushed. Experimental results show that the particle size and the location of the different particles are pressed, will make a change in contact resistance.

Abstract: Dust particles from the air in the electrical contact caused more and more problems. To a large extent reduce the reliability of the system. In order to study the impact of these issues, we need to analyze and discuss the dust particles on contact performance of electrical contact materials. In this paper, under static conditions with 150-212μm of the silica particles analyzed and discussed, represented by the pressure difference, particle size, being suppressed will lead to a different location of the static contact resistance and analysis of particle size of the scope of what the content of easily crushed. Experimental results show that the particle size and the location of the different particles are pressed, will make a change in contact resistance, another analysis gives easily be crushed particle size range is 150-300μm.

Abstract: Spherical niobium powders were synthesized by (RF) argon plasma with irregular niobium powders in this paper. The objective of the present work was to investigate how the feeding rate influence the spheroidization efficiency. The phase composition, morphology and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser micron sizer (LMS). The results show that niobium powders after plasma processing have good dispersity and smooth surfaces, and their spheroidization ratio is almost 100%. The apparent density and flowability of the powder with the spheroidization efficiency 100% is 4.35 g/cm³ and 12.51 s/(50g), respectively. With the increasing of the feeding rate, the spheroidization ratio of niobium powders drops gradually.

Abstract: Rigid-plastic finite element was used to investigate the effect of channel inner angle on aluminum ECAP processing. The simulation results demonstrate that distribution of maximum principal stress was non-homogeneous no matter with 90° inner angle or 120° inner angle. For the both inner angle values, material located at the front-end of workpiece flow easily and material located at the top of die channel corner flow difficultly, which were well agreed with plastic mechanics and experiment. The inhomogeneity of maximum principal distribution in ECAP workpiece processed with die channel inner angle of 90° was more severe than that with die channel inner angle of 120°.

Abstract: Solidification experiment a graphite mold was carried out on ternary alloy Al-4.61Cu-0.92Si and typical dendrite microstructure was obtained. The influence of heat treatment on microsegregation between the dendrite, and the amount and morphology of the non-equilibrium eutectic phases were studied. Line scans results shows that the dendrite microsegregation disappeared after heat treatment under temperature near the ternary eutectic point. And the amount of eutectic phases is decreased obviously and the morphology of most θ-phase is changed from normal pattern to sphere or nearly spherical.

Abstract: An experimental study was performed to analyze the feasibility of heat pipe cooling in creep feed grinding applications. A new type of grinding wheel is developed to enhance the heat transfer of the grinding contact zone then decrease the grinding temperature. The performance of the new type grinding wheel was evaluated by measuring the grinding temperature when it was creep feed grinding the Ti-6Al-4V Alloy and the experimental results were compared with an ordinary grinding wheel. Results of the comparative study indicated that the use of enhanced cooling technology in a grinding wheel can decrease the grinding temperature significantly thus avoid the surface burning in grinding.

Abstract: Analysis tools of microstructure and mechanical properties were used to study ZL102 that was modified by Sr and without modification. The experiment shows that the morphology of eutectic silicon and α-Al phase of the modified alloy have greater changes than that without modification. With the added amount of Sr increases, the morphology of the eutectic silicon changes from sheet into flakiness and fibrous, and finally the fine fiber; α-Al phase increased and showed a small short rod distribution. The optimized technology of Sr modification agent is 0.05%Sr addition, the tensile strength of modified alloy is 218.5 MPa, and the elongation is 2.8%.