作者：
L.A DobrzańskiM AdamiakA ZarychtaSilesian Technical University
Institute of Engineering Materials and Biomaterials Division of Materials Processing Technology and Computer Techniques in Materials Science Kanarskiego St. 18 a 44-100 Gliwice Poland
This paper presents the results of investigations regarding the phase transformations occurring during the heat treatment of W-Mo-V + Si + Nb high-speed steels. It was found that investigat...
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This paper presents the results of investigations regarding the phase transformations occurring during the heat treatment of W-Mo-V + Si + Nb high-speed steels. It was found that investigated steels demonstrate their maximum secondary hardness, about 66 HRC, in connection with the precipitation of M 4 C 3 carbides in tempered martensite after austenitizing at 1240°C and tempering at 540–570°C. The paper presents also results of investigations regarding the erosion resistance of TiN and Ti(C,N) PVD coatings deposited on the investigated steels. TiN and Ti(C,N) coatings deposited in the PVD process yield, respectively, three and seven times greater erosion resistance of the steel surface and demonstrate good adhesion to the investigated steels forming the substrate. Quantitative metallography methods as well as mass loss and created craters 3-D measurements were employed to evaluate the erosion resistance of the investigated coatings. It was found that the surface topography influences the erosion resistance of PVD vacuum arc method coatings. The investigated coatings are not affected by the type of the substrate high-speed steels.
In this study the performance of reactive ion etching (RIE) and magnetically enhanced reactive ion etching (MERIE) processes in pregate oxidation etching of the field oxide are compared. The comparison is carried out ...
In this study the performance of reactive ion etching (RIE) and magnetically enhanced reactive ion etching (MERIE) processes in pregate oxidation etching of the field oxide are compared. The comparison is carried out through metal–oxide–semiconductor (MOS) characterization of oxides and interfaces formed on etched silicon surfaces. The results revealed differences in the outcome of RIE and MERIE processes with the latter displaying overall superior characteristics. MERIE induced surface damage is shallower, and is mostly removed during oxide growth. RIE damage propagates deeper into the Si bulk and still influences the MOS devices even after the top Si layers are converted into the oxide. The results obtained emphasize the importance of adequate cleaning of silicon surfaces following RIE/MERIE processes.
作者：
SWALLOM, DWSADOVNIK, IGIBBS, JSGUROL, HNGUYEN, LVVANDENBERGH, HHDaniel W. Swallomis the director of military power systems at Avco Research Laboratory
Inc. a subsidiary of Textron Inc. in Everett Mass. Dr. Swallom received his B.S. M.S. and Ph.D. degrees in mechanical engineering from the University of Iowa Iowa City Iowa in 1969 1970 and 1972 respectively. He has authored numerous papers in the areas of power propulsion and plasma physics and currently is a member of the Aerospace Power Systems Technical Committee of the AIAA. Dr. Swallom has directed various programs for the development of advanced power generation systems lightweight power conditioning systems and advanced propulsion systems for marine applications. His previous experience includes work with Odin International Corporation Maxwell Laboratories Inc. Argonne National Laboratory and the Air Force Aero Propulsion Laboratory. Currently Dr. Swallom is directing the technical efforts to apply magnetohydrodynamic principles to a variety of propulsion and power applications for various marine vehicles and power system requirements respectively. Isaac Sadovnikis a principal research engineer in the Energy Technology Office at Avco Research Laboratory
Inc. a subsidiary of Textron Inc. He received his B.S. in engineering (1974) B.S. in physics (1975) M.S. in aeronautics and astronautics (1976) and Ph.D. in physics of fluids (1981) at the Massachusetts Institute of Technology. Dr. Sadovnik has been involved in research work funded by DARPA concerning the use of magnetohydrodynamics for underwater propulsion. He has built theoretical models that predict the hydrodynamic behavior of seawater flow through magnetohydrodynamic ducts and their interaction with the rest of the vehicle (thrust and drag produced). In addition Dr. Sadovnik has been involved in research investigations geared toward the NASP program concerning the use of magnetohydrodynamic combustion-driven accelerator channels. Prior to joining Avco Dr. Sadovnik was a research assistant at MIT where he conducted experimental and
Magnetohydrodynamic propulsion systems for submarines offer several significant advantages over conventional propeller propulsion systems. These advantages include the potential for greater stealth characteristics, in...
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Magnetohydrodynamic propulsion systems for submarines offer several significant advantages over conventional propeller propulsion systems. These advantages include the potential for greater stealth characteristics, increased maneuverability, enhanced survivability, elimination of cavitation limits, greater payload capability, and the addition of a significant emergency propulsion system. These advantages can be obtained with a magnetohydrodynamic propulsion system that is neutrally bouyant and can operate with the existing submarine propulsion system power plant. A thorough investigation of magnetohydrodynamic propulsion systems for submarine applications has been completed. During the investigation, a number of geometric configurations were examined. Each of these configurations and mounting concepts was optimized for maximum performance for a generic attack class submarine. The optimization considered each thruster individually by determining the optimum operating characteristics for each one and accepting only those thrusters that result in a neutrally buoyant propulsion system. The results of this detailed optimization study show that the segmented, annular thruster is the concept with the highest performance levels and greatest efficiency and offers the greatest potential for a practical magnetohydrodynamic propulsion system for attack class submarines. The optimization study results were used to develop a specific point design for a segmented, annular magnetohydrodynamic thruster for an attack class submarine. The design point case has shown that this thruster may be able to provide the necessary thrust to propel an attack class submarine at the required velocity with the potential for a substantial acoustic signature reduction within the constraints of the existing submarine power plant and the maintenance of neutral buoyancy. This innovative magnetohydrodynamic propulsion system offers an approach for submarine propulsion that can be an important contributio
The tensile properties of the intermetallic compound Ti3Al have been determined in air at several temperatures within the range of 25 to 900 °C. The dislocation structures produced by the various testing conditio...
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