• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.239-243
• /
• 2008

Nonferrous metals have a very important position in industry. At present, parts of shipbuilding, automobile, and aircraft etc. are designed and manufactured accurately, simultaneity need light-weight and high-strength. Aluminum copper alloys are one kind of typical precipitation hardening alloy which has been widely used. It is interesting to investigate transformation behavior of precipitated phase in such kind of alloys under high magnetic field. Transformation of materials under high magnetic field is many different compared with conventional condition. The author prepared the Al-4%Cu alloy.

• Journal of Korea Foundry Society
• /
• v.2 no.1
• /
• pp.12-18
• /
• 1982

The present investigation was made to abtain a fine distribution of Pb Particles in AL - Pb binary alloys , which have a broad miscibility gap and large specific difference, by means of rapid Cooling of the molten alloys. Al-2.4% Pb, Al-5.5wt% Pb and Al-8.0wt % Pb alloy were used. The rapid cooling operation was performed by free falling of homogeneous liquid Al-Ph alloys into the water-cooled copper mold, and thermal analysis was made. Microstructures were observed, and variations of size and number of Pb particles were analysicle analyzer. By the result of examination with the varing cooling rates 100 to $210^{\circ}C/sec$ fine distributions of Pb particles were obtained with high cooling rate. Under same cooling condition, the best rapid cooling effect was recognized in Al-5.5wt% Pb alloy.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.9
• /
• pp.2866-2874
• /
• 1996

In the grinding of difficult-to-materials, the major problmes of conventional grinding are grinding burn, wheel wear, grinding surface crack, loading and glazing, When a conventioanl grinding wheel is used, wheel wear and grinding surface crack easily occur in low heat conductive material and annealed steel. Intermittent grinding is suitable for diffcult-to-matrical such as stainless steel, titanium alloy, aluminum alloy and copper alloy. The purpose of this paper is to develop a new type intermittent wheel of the grinding system for improving the problem of stainless steel grinding, to observe the effect of intermittent grinding on surface quality and grinding characteristics of stainless steel grinding using intermittent grinding wheel. The characteristics of intermittent grinding system improve surface quality, low grinding temperature and low loading.

• Journal of Surface Science and Engineering
• /
• v.4 no.1
• /
• pp.16-23
• /
• 1971

In this study , fluoborte solution consisting of lead fluoborate, tin fluoborate and cupric acetate was used. By addition of small amount of Cu+= ion to the solution, the Cu content of deposition layer was almost controlled less than 5%. The amount of Cu in deposition layer was almost constant without any influence of Pb++ & Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution . Agitation of plating solution & low current density result in the increase of Cu content. Analyzing of microscopic structures and etching tests of the deposited alloy, it was believed that the alloy had a lamellar structure consisting of copper rich lamellar and lead rich layer.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1996.03a
• /
• pp.108-113
• /
• 1996

Conventionally, grinding of stainless steel, aluminium alloy, copper alloy, and titanum alloy is difficult due to the mechanical properties such as low hardness, high toughness which result in the loading of wheel and the poor surface finish. In order to grind this sort of materials easily, discontinuous grinding wheel with multi-porous grooves was newly developed. The multi-porous grooves were formed during wheel production. This discontinuous grinding wheel drastically increases the grinding performance. It is desirable to use the discontinuous grinding wheel when grinding materials with high efficiency and accuracy which is impossible by conventional wheels. In this paper, the construction and manufacturing method of grinding wheel with multi-porous grooves are explained. The grinding charateristics of discontinuous grinding wheel was also illustrated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.233-236
• /
• 2005

Rotor in small-medium induction motor has been usually manufactured by aluminum diecasting. In order to improve efficiency of induction motors, newly developed Cu-Ca alloys have been investigated. The electrical conductivity in the Cu alloys containing Ca less than $1.0wt\%$ was higher than $80\%$ IACS. Cu-Ca alloy is desirable for the thixoforming process because it has wide semi-solid range over $150^{\circ}C$. In this study, Cu-rotor with thixoforming process was developed to replace the conventional aluminum diecasting rotor. Analysis microstructure of thixoforming rotor. effect of incomplete filling defect on the efficiency of induction motor was discussed.

• Journal of Surface Science and Engineering
• /
• v.42 no.5
• /
• pp.246-249
• /
• 2009

Cu-Ti alloys with titanium in the range of 0.5-6.0 wt% were developed to evaluate the effect of the titanium content and heat treatment on microstructure, hardness, and electrical conductivity. The hardness of the Ti-added copper alloys generally increased with the increase in titanium content and hardening was effective up to the 2.5 wt%-Ti addition. Microstructural examination showed that the second phase of $Cu_4Ti$ started to precipitate out from the 3.0 wt% Ti-addition, and the precipitate size and volume fraction increased with further Ti addition. Aging of the present Cu-Ti alloys at $450^{\circ}C$ for 1 h increased the hardness; however, the further aging up to 10 h did not much change the hardness. In the present study, it was inferred that in optimal Ti addition and aging condition Cu-Ti alloy could have the hardness and electrical conductivity values which are comparable to those of commercial Cu-Be alloy.

• Journal of Welding and Joining
• /
• v.15 no.4
• /
• pp.90-98
• /
• 1997

A copper-tungsten sintered alloy(Cu-W) has been friction welded to a tough pitch copper in order to investigate the effect of friction pressure on bonding strength and a charicteristic of fracture. The tensile strength of the friction welded joint was increased up to 90% of the Cu base metal under the condition of friction time 1.2 sec, friction pressure 4.5kgf/$\textrm{mm}^2$ and upset pressure 10kgf/$\textrm{mm}^2$. From the results of fracture surface analysis, the increase of friction pressure could remarkably decrease the force and the time to be normally acted on weld interface. The W particles which were included in the plastic zone of Cu side could induce fracture adjacent to the weld interface because their existance in Cu induces a decrease in available section area and an increase in notch effect. Therefore, the tensile strength was decreased at high friction pressure (6kgf/$\textrm{mm}^2$) because the destruction of W was increased by an increase in mechanical force and crack was formed at weld interface.

• Electrical & Electronic Materials
• /
• v.9 no.3
• /
• pp.291-297
• /
• 1996

The surface properties of AI(Si, Cu) alloy film after plasma etching using the chemistries of chlorinated and fluorinated gases with varying the etching time have been investigated using X-ray Photoelectron Spectroscopy. Impurities of C, Cl, F and O etc are observed on the etched AI(Si, Cu) films. After 95% etching, aluminum and silicon show metallic states and oxidized (partially chlorinated) states, copper shows Cu metallic states and Cu-Cl$_{x}$(x$_{x}$ (x$_{x}$ (1

• Tribology and Lubricants
• /
• v.27 no.2
• /
• pp.88-94
• /
• 2011

The tribological characteristics of the swash plate surface of a compressor which is for automobile were investigated. For surface treatments, PTFE and $MoS_2$ are used as a solid lubricant, together with copper alloy. Test condition is set considering actual driving condition. Wear testing is conducted using pin on disk type tester, and the coefficient of friction and the temperature on friction surface are measured. Also, to determine the wear patterns, cross-section of friction surface is analyzed by SEM(scanning electrode microscope). The $MoS_2$, both at dry and lubricated conditions, friction surface and the coefficient of friction maintained rather stable results. But, the PTFE, at oil less condition, sample resulted in rather unstable condition. In case of copper alloy, quite higher friction coefficients(higher than 0.1) were obtained at dry condition. At the temperature of $125^{\circ}C$, seizure has occurred.