Copper Drum Research Articles

The Degree of Metallic Alloys Crystallinity Formed under Various Supercooling Conditions

Amorphous metal alloys play an important role in the electrical industry. Studies show the presence of an insignificant proportion of crystals in alloys that are amorphous from the point of view of X-ray diffraction analysis. The crystals significantly affect the mechanical and magnetic properties of amorphous alloys. Therefore, within this work, a comprehensive approach has been developed to determine the degree of crystallinity of amorphous alloys based on theoretical and experimental methods. The study is based on the mathematical model of supercooled melt crystallization previously developed by the authors, which takes into account the patterns of crystal formation and their diffusion and diffusionless growth, taking into account the mutual influence of growing crystals on each other. The mathematical model also takes into account the melt cooling mode when producing amorphous ribbons by cooling the melt on a rotating copper drum. The calculation results have been verified by experiments based on the new technique developed by the authors for calorimetric studies of amorphous ribbons. The developed methodology allows us to determine not only the average fraction of the crystals in a ribbon, but also the patterns of crystal distribution along its thickness as well as the patterns of changes in the proportion of the crystals in ribbons depending on the melt cooling mode.

Study of the local magnetic properties of Fe(Ni,Cu)(SiB) ribbon amorphous alloys produced by ultrafast cooling

Magnetic force microscopy was used to investigate the effect of magnetic pulse treatment on the local magnetic properties of the surface of ribbon amorphous Fe(Ni,Cu)(SiB) alloys obtained by ultrafast cooling by melt spraying on a rotating copper drum.

Изучение влияния слабых импульсов магнитного поля на локальные свойства ленточных аморфных сплавов Fe(Ni, Cu)(SiB)

Atomic force microscopy and magnetic force microscopy have been used to study the influence of weak magnetic field pulses on the local properties of ribbon amorphous Fe(Ni, Cu)(SiB) alloys about 100 µm thick, 10 mm wide, and 50 mm long, which were obtained by ultrafast cooling of the melt on a rotating copper drum. On the surface of the tape adjacent to the copper drum, there were practically no areas with low rough-ness, which did not allow subsequent studies of this side of the tape by magnetic force microscopy. This method was used to investigate another, free surface of the foil, which was not adjacent to the copper drum and did not have significant roughness. Prior to the impact of magnetic field pulses on the foil, no magnetic contrast was observed on the free side of the ribbon. After magnetic pulse processing, a magnetic contrast was registered on this side of the foil: stripe domains 0.6–0.8 μm wide became visible, and closing domains, became visible on structural defects, wedge-shaped Neel domains, from 1 µm to 1.6 µm wide. The results of the study allow us to say that the magnetization reversal losses are to a large extent associated with losses due to eddy currents and are associated with the domain width, which depends slightly on the modes of magnetic pulse processing. The obtained results of the research can be used to refine the method for relieving stresses arising in the process of manufacturing amorphous ribbons.

The application and Heritage of Copper Drum Culture in Nanning Primary School Art Classroom

Copper drums have been baptized by thousands of years of wind and rain, and festival activities related to copper drums are still active in some regions of China, so it is of practical significance to study the inheritance and innovation of copper drum art. The heritage needs to start from children, and elementary school teachers need to let children receive the culture of copper drums from an early age and feel the important role of copper drums in national festival activities in order to better inherit the culture of copper drums and promote the wide circulation of traditional cultural symbols in Guangxi region. This study takes the art curriculum resources of Nanhu Elementary School as an entry point, explains from the perspective of developing regional folk art curriculum resources according to local conditions, and further considers how to transform the copper drum cultural resources into art curriculum resources by analyzing excellent cases of local school-based curriculum development and utilization, deepening students' sense of identification with their native art and making them consciously take up the mission of cultural inheritance and promotion.

An Investigation of the Production Technique of the Copper Drum as a Percussion Instrument

A copper drum evolved as a percussion instrument from an ancient bronze drum. It inherits the fine casting technology of a copper drum and gives the law of copper drum to form. In the 1980s, influenced by the successful reproduction of Chinesisches Glockenspiel, Huang Zhongyu and Zhang Yingzhong improved the sound of copper drums by combining with the customized beating of bronze drums in the Zhuang region of Guangxi and developed the first generation of fixed tone bronze drums capable of producing modern scales. Out of their love for the bronze drum culture, Tan Anyi and Ya Yunyong, from Donglan Middle School in Guangxi,devoted themselves to seek the sound of bronze drums that modern people could understand. After several experiments, they independently developed a musical bronze drum capable of producing an octave in 2009. The twelve-uniformized tone of the bronze drum could be better integrated with modern stage performance. This would make it possible to present the drum as a percussion instrument as well as reveal its production techniques to audiences, which is the best way to investigate and record its production techniques and analyze its tuning principle.

Evaluation of Electromagnetic Launcher Contact Resistance Using a Design of Experiments Approach

Many different approaches have been made to modeling the parameters associated with electromagnetic launchers (EMLs). This article proposes an approach going back to the first principles of design, which is meant to simplify the process of determining the significant factors used to optimize an EML. A screening design of experiments (DOE) is a tool that can be used in determining the statistically significant factors for design. In this article, we used the screening DOEs to examine sliding contacts against a copper drum and a copper coil, with resistance as the parameter being optimized. The results were nominal for the simple copper drum. It was discovered that sliding electrical contacts across a coil may present a closer representative test bed of a helical electromagnetic launcher (HEML) than does the conventional copper drum approach, yielding a more complex result requiring more parameterization and characterization.

Microstructure and Properties of Nd – Fe – B Alloys Produced by Strip Casting and of Permanent Magnets Fabricated from Them

Optimization of the microstructure of plates from alloys of the R – Fe – B (R: Nd, Dy) system obtained by pouring the melt onto a rotating copper drum by the method of strip casting is studied. The strip-cast Nd – Fe – B and Nd – Dy – Fe – B alloys with optimized microstructure are used to produce high-energy and high-coercivity sintered magnets.

HTS Vernier Machine for Direct-Drive Wind Power Generation

A high-temperature superconducting (HTS) vernier machine is proposed for direct-drive wind power generation. The rotor adopts conventional configuration where high-temperature superconductors are used for field winding, while the stator has toothed-pole structure, which is composed of copper drum windings and iron core, thus combining advantages of both HTS and vernier machines. With the employment of finite-element analysis, the electromagnetic performances of the proposed machine are evaluated and quantitatively compared with a conventional HTS generator. It is found that the HTS vernier machine can provide higher average torque, lower pulsation torque, higher efficiency and smaller short circuit current, among which the last one is rather large in conventional HTS machines.

Microstructure and thermoelectric properties of CoSb2.75Ge0.25−xTex prepared by rapid solidification

Since the vibration modes of the pnicogen rings in CoSb3-based skutterudites fall within the range of frequencies of heat-carrying phonons, disruption of the rings by doping should have a strong influence on heat transport in this material. To test the premise, single-phase double-doped CoSb2.75Ge0.25−xTex (x=0.125–0.20) compounds were synthesized by combining melt spinning with a spark plasma sintering method. Following the melt-spinning process, the side of the ribbons contacting the copper drum is featureless and reflects its amorphous nature while the free surface of the ribbons is composed of 30–80nm grains. After spark plasma processing the average grain size of the bulk samples is about 200nm. High-resolution transmission electron microscopy images show an in situ nanostructure consisting of circular, 15nm diameter dots of Te- and Ge-enriched skutterudite phase embedded in the skutterudite matrix. Transport properties were measured from 2 to 800K as a function of Te and Ge content on the pnicogen (Sb) rings and the results were correlated with the structural data. Double-doping on pnicogen rings with Ge and Te, and using melt-spinning processing, results in binary skutterudite compounds that possess an impressive figure of merit of ZT∼1.1 at 750K.

Proof-of-principle experiments on the concept of moving-surface plasma-facing components—hydrogen recycling over a titanium-gettered rotating drum

In the magnetic fusion community much attention has recently been directed to particle control in the existing confinement experiments, as it is recognized that the core plasma performance can directly be affected by the edge conditions. However, it is still true that there is no clear strategy to cope with the needs for steady-state reactor operation. That is that, due to the saturation nature, wall conditioning such as boronization is not applicable for fuel and impurity particles control in steady-state devices, requiring a start from enabling concepts development. As a possible solution, the concept of moving-surface plasma-facing components (MS-PFCs) was proposed in our previous work and in the present work proof-of-principle experiments have been conducted. In this concept, the plasma-facing surface is mechanically circulated out-of-pile for regeneration of particle capturing capabilities by coating getter films on it. A prototypical MS-PFC test unit has been constructed for these proof-of-principle experiments, employing a rotating copper drum as the moving surface and titanium as the getter material. It has been indicated that, from H α light intensity data taken in front of the rotating target, relative to no getter cases, approximately 6% reduced hydrogen recycling has been achieved at steady state. In support of these data, a first-order particle balance model predicts a 7% reduction in hydrogen recycling.

アルミニウム‐遷移金属合金の急冷凝固フレークの製造と性質

As the first step of production of P/M aluminum materials, an experimental apparatus has been made for continuous production of splat quenched aluminum alloy flakes. The apparatus, by which aluminum alloy melt is atomized into small droplets and subsequently splat quenched on a rotating water-cooled copper drum, is capable of producing flakes at a rate of 5 g/s. Splat quenched flakes of Al-218 wt%Fe, Al-511 wt%Mn and Al-818 wt%Ni alloys were produced and their properties were examined.A typical flake is approximately 10 mm in diameter, and its thickness is about 30 μm at the center and increases near the edge. From the measurement of eutectic interlamellar spacing of Al-33 wt%Cu alloy flakes, the cooling rate was estimated as 3×105°C/s at the center. The formation of primary intermetallic compounds is suppressed in splat quenched flakes of all the alloys tested. The structures of splat quenched flakes of Al-Fe and Al-Ni alloys are fine cellular and rod or lamellar eutectic, respectively. A supersatulated solid solution is formed in Al-Mn alloys, which decomposes upon heating at above 350°C. The hardness of as splat quenched flakes, which is higher for the higher content of alloying elements, is thermally stable up to 350°C in Al-Fe and Al-Mn alloys.

溶射ガンを用いたＡｌ粉およびＡｌ合金粉の製造とその粉末特性

Flame spraying gun was applied to the production of pure Al and AI-5.4%Si alloy powders. For the purpose of obtaining rapidly cooled powders the metallic sprays were injected into static water in stainless steel vessel, dynamical water and dynamical liquid nitrogen in rotary copper drum, respectively.Some characteristics of the powders obtained were estimated with reference to the particle size distribution, particle shape, degree of oxidation and cooling rate of powders.The shape of the powders obtained from this experiment was similar to that of commercial water atomized Al powder. The cooling rate of Al-5.4%Si powder estimated from the dendrite arm spacing was about 104 K/s, and the solubility of Si in Al powder measured at room temperature was about 3 wt% which was approximately twice as much as that of equilibrium state at the eutectic temperature of 830 K.

Preferred orientation of rapidly frozen metals

When metals are rapidly frozen, a preferred orientation may be observed in the grains of the chilled surface. The extent and stability of this preferred orientation has been examined, using X-ray diffraction, for a variety of metals produced by melt-spinning i.e., by directing a fine stream of liquid against a rapidly rotating copper drum to produce a thin tape. It is shown that metals with a hcp crystal structure tend to display the greatest degree of preferred orientation. In particular, the degree of preferred orientation displayed by as-spun zinc ribbon is such that it could be used as an inexpensive crystal analyser for X-ray diffraction, comparing favourably with quartz.

The β → α Transition in Rapidly Quenched Sn-Ge Alloys

ABSTRACTDilute Sn-Ge alloys were prepared as ribbons by meltspinning using a 4" copper drum. They were then transformed into grey tin at 242 K in the as-cast-condition, and after annealing. It is shown that germanium: (1) when in solid solution impedes β → α transformation; (2) when in solid solution cannot effect nucleation; and (3) has a solubility in α-Sn in excess of 1 wt. % Ge.In addition it is proposed that β → α transformation is restricted because the presence of germanium strengthens the β-Sn matrix.

A gas atomization spray quenching technique for bulk splat cooling

Apparatus for the production of large quantities of splat- cooled material is described. The technique involves atomizing a liquid alloy stream by high velocity gas jets and quenching the atomized droplets by a rotating watercooled copper drum. In its present form, the apparatus is capable of splat quenching approximately 2 kg of alloy at a rate of 80 g s-1 and the scale can be readily increased. The performance of the apparatus is discussed on the basis of experience with Al-Fe alloys.

The formation of wedges of displaced metal between sliding metal surfaces

In order to obtain more detailed information about the mechanism of sliding, the regions of interaction between sliding metal surfaces were observed through a low power microscope. In experiments with a hemispherical copper rider sliding against a large slowly-rotating copper drum, it was found that most of the time during sliding the drum and rider were held apart by a wedge of displaced metal which was formed between them. Whenever this wedge broke away from the rider, a new wedge was quickly formed to replace it. The formation of similar wedges has subsequently been observed to occur in experiments with a variety of other metals and with pairs of flat metal surfaces. When pairs of flat metal surfaces slide, several wedges are formed at different places between each pair of surfaces. Further investigation using metallographic techniques has shown that the adhesive junctions which are formed when the metal surfaces are first placed in contact do not break when the surfaces begin to slide. The relative motion of sliding is accommodated by plastic shearing of the metal near the junctions. The shearing takes place in a direction slightly inclined to the surfaces, and this causes the formation of the wedges.

Interaction of Sliding Metal Surfaces

The friction of sliding metal surfaces is often attributed to the formation and shearing of welded junctions between the surfaces. This paper describes a more detailed investigation of the phenomena which occur in the junctions. Experiments were performed with a hemispherically ended copper rider sliding against the surface of a large cylindrical copper drum. Observation of the sliding contact through the microscope shows that most of the time during sliding, the drum and rider are held apart by a wedge of displaced metal from the drum, which becomes trapped between them. Whenever a wedge escapes from between the drum and rider, another wedge forms rapidly to replace it. The wedges are also observed with several other combinations of metals, and with pairs of flat copper surfaces. Sections cut through the wedges and adjacent copper contact members were examined. It is found that the shearing of the metal by which the sliding proceeds occurs in a direction slightly inclined to the drum surface. This causes the formation and growth of the wedges. The shearing is primarily a continuous plastic deformation process somewhat similar to the shearing process by which the chip is generated in the cutting of ductile metals with machine tools. It is possible that the adhesion between the rider and wedge may often be weaker than the junctions usually assumed to be responsible for friction. Wear debris is observed to be produced in a number of different ways.