Mixed-powder Method Research Articles

Conditions of Infiltration and Baking of 3D Printed Plaster Molds for Centrifugal Mixed-Powder Method

Conditions of Infiltration and Baking of 3D Printed Plaster Molds for Centrifugal Mixed-Powder Method

Fabrication of Al-Based Composites by Centrifugal Mixed-Powder Method and Their Application for Grinding Wheels

In this study, Al-based metal matrix composite (MMC) with diamond and cBN abrasive grains was fabricated by a centrifugal mixed-powder method (CMPM). Two types of CMPM experiments with and without consolidated part were carried out. It was found that the MMC dispersed with diamond and cBN abrasive grains can be successfully fabricated by CMPM. In case of CMPM without consolidated part, the homogeneous distribution of the abrasive grains along hoop direction in the MMC could not be achieved due to slumping of mixed-powder by gravity. On the other hand, modified CMPM using consolidated part could fabricate a MMC with uniform distribution of abrasive grains along hoop direction. Grinding wheels were manufactured using fabricated MMC samples, and drilling experiments were carried out on carbon fiber reinforced plastic (CFRP). It was found that the better drilling performance was found for the Al/Diamond grinding wheel rather than Al/cBN grinding wheel. Therefore, it can be concluded that the grinding wheel was not subjected at high temperature even though the drilling was carried out under dry condition.

Joining of AlN and Al with Compositional Graded Layer by Centrifugal Mixed-Powder Method

In this study, joining of AlN and Al with compositional graded layer is made by centrifugal mixed-powder method (CMPM). The mixed-powder of AlN particles and Al particles is inserted into a spinning mold with bulk-shaped AlN, and then molten Al is poured into the spinning mold with the mixed-powder and bulk-shaped AlN. As a result, the molten Al penetrates into the space between the mixed-powder by the centrifugal force, and at the same time, the Al particles can be melted by heat from the molten Al. Then AlN and Al can be joined with compositional graded layer after solidification. Micromechanics-based analysis is also employed to understand the thermal stress relaxation by the compositional graded layer.

Formation of compositional gradient in Al/SiC FGMs fabricated under huge centrifugal forces using solid-particle and mixed-powder methods

Formations of graded distribution of SiC ceramic particles within the hollow cylindrical shaped Al/SiC functionally graded materials (FGMs) fabricated by centrifugal solid-particle method (CSPM) and centrifugal mixed-powder method (CMPM) under huge centrifugal force are experimentally and theoretically investigated. The movement of SiC ceramic particles in viscous liquid under centrifugal force is explained based on Stoke's law. The effect of compositional gradient of particles on viscosity is taken into account. Also, the effect of temperature distribution on viscosity and density are considered. A computer code to simulate the formation of compositional gradient in the Al/SiC FGMs fabricated by CSPM and CMPM is developed. From the results, it is found that the volume fraction of SiC ceramic particles can be graded from the inner to the outer surface of hollow cylindrical shaped Al/SiC FGMs by CSPM. Meanwhile by CMPM, the SiC ceramic particles can be dispersed on the outer surface of hollow cylindrical shaped Al/SiC FGMs. The graded distribution in Al/SiC FGMs under huge centrifugal force is found to be significantly affected by the mold temperature but less affected by the temperature of molten Al and casting atmosphere.

Conversion of multi-layered Mg-based carrier to hydrogen storage performance

The mixed powder method and covering method were adopted to prepare a composite that has hydrogen storage properties. In the experimental process, the alloy phases Mg2Ni and NiTi generated regularly; the penetration of the hydrogen atoms to the material was considered as the adsorption of the material to the hydrogen atoms; the original thermodynamic equation was edited; the crystal phases were optimized by adjusting the parameters about the material composition and gas concentration, so that providing advantageous channels of the hydrogen atoms in and out to improve the hydrogen storage properties. The results showed that integer multiples adjustment to trace element Ti could make hydrogen storage properties maximizing optimize and have controllability for the capacity and rate of hydrogen storage according to the newly editing equation. The innovation was to edit out equation that can improve the hydrogen storage properties through adjusting three parameters of trace element Ti, adsorption and penetration to find the most optimal condition improving the hydrogen storage properties.

Effects of Particle Size on Fabrication of Al-TiO<sub>2</sub> Functionally Graded Materials by Centrifugal Mixed-Powder Method

As one of processing methods of functionally graded materials (FGMs), centrifugal mixed-powder method has been proposed. The centrifugal mixed-powder method is the casting process combined of centrifugal casting and powder metallurgy. This processing method has advantage that fine ceramics-particles, whose wettability with matrix melt is low, can be compounded into metallic material. However, effects of particle size on microstructure and mechanical properties of the FGMs fabricated by the centrifugal mixed-powder method are unclear. In this study, two kinds of Al-TiO2 FGMs rings are fabricated by the centrifugal mixed-powder method. One contains TiO2 particles having similar diameter with Al matrix particles (hereafter, small different-size (SD) TiO2 particles), and the other one compounds TiO2 particles with much smaller diameter than Al matrix particles (hereafter, large different-size (LD) TiO2 particles). In case of the Al-TiO2 FGMs ring containing SD-TiO2 particles, the TiO2 particles are homogeneously dispersed in Al matrix on outer surface of the ring. On the other hand, the TiO2 particles in the Al-TiO2 FGMs ring with LD-TiO2 particles are distributed along grain boundary of Al matrix. Moreover, Vickers-hardness and wear resistance around outer surface of the Al-TiO2 FGMs ring containing the SD-TiO2 particles is higher than that of the Al-TiO2 FGMs ring with LD-TiO2 particles. Since Al particles in the mixed-powder with LD-TiO2 particles are surrounded by the TiO2 particles, the Al particles can be hardly melted by heat of molten Al at casting process. As a result, the Al-TiO2 FGMs ring with LD-TiO2 particles has low hardness and wear resistance. Therefore, it is found that TiO2 particles having similar diameter with Al matrix particles are more suitable for fabrication of the Al-TiO2 FGMs rings.

ダイヤモンド砥粒Al基メタルボンド傾斜機能砥石によるCFRPの穴あけ加工

Carbon fiber reinforced plastic (CFRP) is increasingly used as a structural material in the aircraft industry due to its superior properties such as low weight, high strength, good toughness and so on. Drilling of CFRP is the most common post process of structural parts of aircraft. Recently, gyro-driving grinding wheel system has been developed as a new drilling system for CFRP. This system provides holes with high precision on CFRP without delamination and burr formation. In the gyro-driving grinding wheel system, a grinding wheel was used, instead of drill bits for drilling. In our previous study, Cu-bonded grinding wheel with diamond abrasive grains was fabricated by centrifugal mixed-powder method, which is an application of centrifugal casting. However, designed distribution of diamond grains in the grinding wheel cannot be obtained because of the influence of gravity on the mixed-powder set in the caster. In this study, Al-based grinding wheel with designed distribution of the diamond grains has been fabricated by the centrifugal mixed-powder method with preform.

609 遠心力混合粉末法にて作製したグラファイト分散型Cu-Ti基複合材料の時効硬化による高強度化(SS1-2 英語プレゼンテーションセッション(2))

609 遠心力混合粉末法にて作製したグラファイト分散型Cu-Ti基複合材料の時効硬化による高強度化(SS1-2 英語プレゼンテーションセッション(2))

608 遠心力混合粉末法を用いて作製したAl基cBN砥石によるCFRPの穴あけ加工(SS1-2 英語プレゼンテーションセッション(2))

608 遠心力混合粉末法を用いて作製したAl基cBN砥石によるCFRPの穴あけ加工(SS1-2 英語プレゼンテーションセッション(2))

Improvement of bonding force between abrasive grains and matrix in Cu/diamond composite fabricated by centrifugal mixed-powder method

Improvement of bonding force between abrasive grains and matrix in Cu/diamond composite fabricated by centrifugal mixed-powder method

OS8-40 Improvement of Bonding Force Between Abrasive Grains and Matrix in Cu-Based Diamond Grinding Wheel Fabricated by Centrifugal Mixed-Powder Method(Advanced materials,OS8 Fatigue and fracture mechanics,STRENGTH OF MATERIALS)

OS8-40 Improvement of Bonding Force Between Abrasive Grains and Matrix in Cu-Based Diamond Grinding Wheel Fabricated by Centrifugal Mixed-Powder Method(Advanced materials,OS8 Fatigue and fracture mechanics,STRENGTH OF MATERIALS)

305 遠心力混合粉末法を用いて作製したAl基cBN傾斜機能砥石によるCFRPの穴あけ加工

305 遠心力混合粉末法を用いて作製したAl基cBN傾斜機能砥石によるCFRPの穴あけ加工

Fabrication of Metal-Based Functionally Graded Grinding Wheel by a Centrifugal Mixed-Powder Method

Metal-bonded diamond grinding wheel was fabricated by a centrifugal mixed-powder method. The centrifugal mixed-powder method is a novel and effective casting process to obtain functionally graded material (FGM). At the beginning, we performed fundamental experiments using Al-Si alloy system for the purpose of knowing the migration behavior of mixed-powder under centrifugal force. Al-Si hypereutectic alloyed-powder or mixed-powder of Al and Si particles was placed into the mold, and then Al molten metal was cast under a centrifugal force. Cross sectional microstructure observation and quantitative analysis of Si content were conducted using an electron probe microanalyzer. Amount of Si decreased with receding from a mixed-powder region. Si concentration gradient in the sample fabricated Al-Si powder was smaller than the one fabricated using mixed-powder of Al and Si particles. Subsequently, φ 20 mm Cu/diamond grinding wheel was fabricated by the casting method. Graded diamond distribution was successfully obtained.

遠心力混合粉末法による傾斜機能材料製造とその工業的応用

遠心力混合粉末法による傾斜機能材料製造とその工業的応用

反応遠心力混合粉末法を利用したマグネシウム基傾斜機能材料の製造

反応遠心力混合粉末法を利用したマグネシウム基傾斜機能材料の製造

J043044 Ti添加によるCU基ダイヤモンド加工砥石の砥粒結合力の改善

Carbon fiber reinforced plastic (CFRP) is used as material for automobile and aircraft. However, it is difficult to work the CFRP due to its too high strjpnth. As drilling process for CFRP, gyro-driving drilling machine has been proposed. Although this drilling machine makes hole in CFRP plate by using grinding wheel, high strjpnth is required for the grinding wheel. Recently, in order to achieve this requirement, Cu-based diamond grinding wheel has been successfully fabricated by centrifugal mixed-powder method. This grinding wheel can make holes for CFRP without delamination and burr, but then the bonding force between Cu matrix and a diamond particle is low. This is because wettability between Cu and diamond is low. In this study, the Cu-based grinding wheels with Cu-Ti matrix have been fabricated. As results, it is found that the addition of Ti into Cu matrix is effective to enhance the bonding force and wear resistance of the Cu-based grinding wheel.

Fabrication of Al/Al3Ti Functionally Graded Materials by Reaction Centrifugal Mixed-Powder Method

Formation of compositional gradient in Al/Al3Ti Functionally graded materials (FGMs) fabricated by the centrifugal method (CM) depends mainly on the centrifugal force and the processing temperature. In this study, a novel centrifugal method, reaction centrifugal mixed-powder method (RCMPM), was proposed to fabricate Al/Al3Ti FGMs under fixed centrifugal force (G=80). The effects of RCMPM processing temperature on the formation of Al3Ti intermetallics, its morphology and its distribution in the fabricated Al/Al3Ti FGMs have been investigated. Fine granular Al3Ti were observed at relatively lower processing temperature while the known coarse platelet-like particles of Al3Ti could be achieved at higher casting temperatures. Moreover, Ti3Al intermetallics compound and unreacted Ti phases are also observed along with Al3Ti particles. In addition, distribution of Al3Ti intermetallics size and their volume fraction showed a significant change when the Al/Al3Ti FGMs processed at different temperatures relative to the liquidus temperature of the master alloy.

Fabrication of Al/Al3Ti Functionally Graded Materials by Reaction Centrifugal Mixed-Powder Method

Formation of compositional gradient in Al/Al3Ti Functionally graded materials (FGMs) fabricated by the centrifugal method (CM) depends mainly on the centrifugal force and the processing temperature. In this study, a novel centrifugal method, reaction centrifugal mixed-powder method (RCMPM), was proposed to fabricate Al/Al3Ti FGMs under fixed centrifugal force (G=80). The effects of RCMPM processing temperature on the formation of Al3Ti intermetallics, its morphology and its distribution in the fabricated Al/Al3Ti FGMs have been investigated. Fine granular Al3Ti were observed at relatively lower processing temperature while the known coarse platelet-like particles of Al3Ti could be achieved at higher casting temperatures. Moreover, Ti3Al intermetallics compound and unreacted Ti phases are also observed along with Al3Ti particles. In addition, distribution of Al3Ti intermetallics size and their volume fraction showed a significant change when the Al/Al3Ti FGMs processed at different temperatures relative to the liquidus temperature of the master alloy.

切削屑を利用した遠心鋳造法のアルミニウムでの検証

We are proposing a centrifugal mixed-powder method as a novel processing technique to fabricate a nano-particle distributed FGM. If the mixed-powder has been changed into machining chips, an eco-centrifugal casting method can be achieved, since the reduction of necessary power for casting will be expected if recycled materials are used in the melting and casting process. Pure Al or Al-Si alloy melt of 750°C or 800°C is poured into the spinning mold with or without the machining chips. It is found that Al pipe can be fabricated by the centrifugal casting with machining chips. It is also found that the machining chips act as the grain-refiner. Although some pores were found for the cast with the machining chips, the defect can be reduced when the mold is preheated. In this way, Al pipes without casting defect can be fabricated by the proposed method.

Fabrication of functionally graded grinding wheel by a centrifugal mixed-powder method for CFRP-drilling applications

We are developing functionally graded grinding wheels fabricated by a centrifugal mixed-powder method. As a first step of this fabrication method, a powder mixture of abrasive particles and metal matrix particles is inserted into a spinning mould. After that, a metal matrix ingot is melted and then the molten metal matrix is poured into the spinning mould with the powder mixture. As a result, the molten metal matrix penetrates into the space between the particles due to the pressure exerted by the centrifugal force. At the same time, the metal matrix powder is melted by the heat from molten matrix poured from the crucible. Finally, a ring-shaped sample with abrasive particles distributed on its surface (functionally graded grinding wheel) can be obtained. In this study, functionally graded grinding wheel fabricated by the centrifugal mixed-powder method will be reported.