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1–10 of about 1210 matches for copper alloy
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FRICTION AND WEAR BEHAVIOR OF A CENTRIFUGALLY CAST LEAD-FREE COPPER ALLOY CONTAINING GRAPHITE PARTICLES (20050664)
Metallurgical & Materials Transactions A V 32A P 2115 – 2125 August 2001
The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 vol pct graphite particles (5 ?m), have been studied. Friction tests were carried out at three different loads of 44. 88, and 176 N using a pin-on-disk testing method for the base copper alloy and the copper-graphite composite against a 1045 steel disk counterface. The friction coefficient. temperature rise. and weight loss of the pin and disk were measured. To understand the wear mechanism, the wear debris and the surfaces of the pin and the disk were analyzed before and after the tests. using scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) analysis. The friction coefficient of the copper-graphite pins was lower than that of the base-alloy pins for all applied loads. which was attributed to the presence of the graphite in the matrix. It was also observed that the presence of graphite in the matrix reduces the transfer of iron from the counterface to the pins. but enhances the transfer of materials from the pins to the counterface. The temperature rise in the counterface running against the base-alloy pins was larger than the temperature rise in the counterface running against the copper-graphite pins, both tested under similar conditions. In addition, the eftect of element transfer on the friction coefficient, variations in the weight of the pins and the counterface, as well as the surface roughness, are attributed to the formation of a graphitic tribolayer on the surface of the copper-graphite pins. An isostrain model predicting the friction coefficient of the composites is proposed, which agrees well with the measurements in the present article as well as with measurements made by other investigators.

Some Properties of Sulfide Dispersed Lead Free Copper Alloy Castings (20083202)
AFS Transactions 2008, Vol. 116, Paper 08-052(03), P299-307
Sulfide dispersed lead free copper alloy castings were prepared and mechanical properties and casting properties were evaluated. In the sulfur added copper alloy, sulfide formed during solidification after the primary alpha-Cu solidification start. The sulfide was dispersed in the matrix. The microstructure of the sulfide dispersion was confirmed by optical microscope and SEM. Elemental distribution was also investigated by WDX. The sulfide was mainly copper sulfide (Cu2S). There were little shrinkage cavity, even if the sulfur content increased. Mechanical properties of sand castings were equal to or above the lead containing castings. Machinability was also equal to the lead containing castings.

DEVELOPMENT OF A COPPER ALLOY COMPOSITION FOR GRAVITY, LOW-PRESSURE, AND HIGH-PRESSURE DIE CASTING (19900747)
Transactions of the American Foundrymen's Society V 98 Paper 90-55 P 327-330, 1990 (4 p)
Described is the derivation, or development, of a copper base alloy for gravity or high pressure die casting that eliminates cracking of the cast metal. Chemical alloying elements and impurity limitations are stated. The resulting alloy is now used worldwide for gravity or die cast sanitary hardware. Also presented are test methods that can be used as a reliable guide that the alloy mixture is correct for obtaining good castings with this copper base alloy.

PROTOTYPING OF SOME COPPER ALLOY PLUMBING COMPONENTS BY GRAVITY AND LPPM CASTING PROCESSES (20000222)
Transactions of the American Foundrymen's Society V 107 Paper No 99-44, P 147-151, 1999 (5 p)
The recent restrictions on the lead content in drinking water have led to the development of low-lead or lead-free copper based alloys for plumbing and electrical applications. Alloys with Bi and Se (SeBiLOYs) could replace the lead-containing red and yellow brass alloys commonly used for plumbing applications. The lead-free SeBiLOY III, which is intended as a substitute for leaded yellow brass (C85800), had better mechanical properties as well as improved corrosion resistance.

A Study on Fillability, Microstructure and Porosity in LFC of B206 Aluminum Copper Alloy (20083251)
AFS Transactions 2008, Vol. 116, Paper 08-023(11), P917-931
B206 aluminum copper alloy has a potential for wider use in the automotive industry due to its light weight and relatively superior mechanical properties as compared to aluminum-silicon alloys. The possibility of casting this alloy via Lost Foam Casting (LFC) has not been investigated in detail. Therefore, the effects of foam types (T170B-standard untreated EPS and T175-brominated EPS), coating types (mica base low permeability high absorption and mica base high permeability high absorption), copper levels (4.5 wt % and 5.0 wt %) and titanium grain refiner addition levels (0.05 wt % and 0.25 wt % as Al- 5%Ti-1%B master alloy) were related to fillability, microstructure and porosity. The metal velocity in the T175 EPS pattern was higher than that in the T170B EPS pattern. For the T175 EPS pattern, the total solidification time was 3% higher and the loss of temperature for decomposition of EPS was lower than those in the case of the T170B EPS pattern. The grain size, porosity level and maximum pore size were quantified using Light Optical Microscopy (LOM) and image analysis. The casting with the T175 EPS pattern showed larger grain size relative to that with the T170B EPS pattern. The porosity level and the maximum pore size decreased significantly when the titanium addition was increased from 0.05 wt % to 0.25 wt % through controlled additions of the Al-Ti-B master alloy. The T175 EPS foam castings with high permeability coating show promise of casting soundness with low porosity.

Antimicrobial Properties of Copper Alloy Surfaces, With a Focus on Hospital-Acquired Infections (20083100)
International Journal of Metalcasting, Vol. 2, Issue 3, Summer 2008, P47-56
Recent laboratory studies show that several bacteria, known to be human pathogens, die when they come in contact with dry copper and copper alloy surfaces at room temperature. The amount of live bacteria drops by several orders of magnitude, to zero, on copper alloys in one to two hours. In contrast, almost no reduction is seen in the concentration of live organisms on stainless steel after several hours and even days. Aluminum, painted and coated surfaces and plastics would also exhibit behavior similar to stainless steel and show no effect. In addition, coatings and other surfaces claiming to be antimicrobial also showed little to no effect. These results suggest the selection of copper alloys for surfaces exposed to human touch can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms. In order to make antimicrobial claims in the United States, the approval of the US Environmental Protection Agency (EPA) is required. The EPA-required efficacy testing is described and the test results are summarized. EPA registration of 275 cast and wrought copper alloys was received on February 29, 2008. It is anticipated that registration will facilitate the introduction of antimicrobial copper alloys in hospitals, nursing homes and other healthcare facilities, as well as schools, and public buildings. Some of the barriers to entry into the healthcare markets are mentioned.

DEFECT ANALYSIS AND EVALUATION OF A COPPER ALLOY PERMANENT MOLD CASTING (19951011)
Transactions of the American Foundrymen's Society V 102 Paper 94-52 P 263-268, 1994 (6 p)
The MTL 50th Anniversary Paperweight was produced by permanent molding. Metals used were silicon brass alloy C87500 and yellow brass alloy C85800. Details of this complex, decorative casting are described and shown. Casting parameters such as mold coating thickness, pouring and mold temperatures, rotation speeds, etc., were established to produce sound castings and to eliminate cracking at edges of letters and junctions of raised edges. Production of the casting was an exercise in solving some problems specific to the permanent mold casting of copper-base alloys.

COPPER-ALLOY METALLURGY IN ANCIENT PERU (20051030)
Scientific American P 80 - 86 July 1991
More than 1,000 years ago civilization in South America was forged out of copper alloys. Recent excavations have revealed many aspects of copper-alloy metallurgy, from mining to smelting to metalworking.

COPPER ALLOY, PARTICULARLY INTENDED FOR DIE-CASTING (19680652)
Canadian Patent No 767,583
The object of the present invention is to provide a copper alloy of a composition such that it is easy to die-cast, that it is easy to work with cutting tools, that it obtains a good resistance to corrosion and obtains satisfactory characteristics. In order to take the best advantage of the desirable properties of the ingredients of the alloy, the composition of the alloy should be the following: copper - 55%, Aluminum - 1.5%, Lead1.4%, Silicon - 0.9%, Arsenic - 0.03%, tin - 1.0%, Zinc - Remainder. For practical industrial usage deviations from this formula can of course be allowed without appreciable changes in the properties. The following limits may be indicated: Copper 62 - 70%, Aluminum 0.3 - 3.0%, Lead 1.0 - 3.5%, Silicon 0.5 - 1.5%, Arsenic 0.02 - 0.1%, Tin 0.5 - 1.5%, Zinc - Remainder. Thus, the copper to zinc ratio, as in conventional copper-zinc alloys, should be at least 2:1 in order that a pure structure should be provided, as in desirable. The upper limit of the copper content is determined by the requirements with respect to die-casting, a high copper content resulting in a higher melting point and a higher wear on the tools. A copper content of 70% is considered maximum.

ACTION OF CHILLS ON SOUNDNESS OF LONG FREEZING RANGE ALUMINUM 4.5% COPPER ALLOY CASTINGS (19740280)
British Foundryman (Jan 1974), p. 10-17
The action of metallic and non-metallic chills on temperature gradients, and solidification gradients set-up during freezing and on soundness of aluminum- 4.5% copper alloy castings was investigated. Results of the investigation indicate that: (i) Casting soundness expressed as percentage porosity or ultimate tensile strength varies linearly with log of average temperature gradient or average solidification gradient; (ii) A linear relationship exists between mean of average temperature gradient or solidification gradient and volumetric heat capacity of the chill; (iii) Average soundness of the casting increases linearly with the increases in volumetric heat capacity of the chill; (iv) Average temperature gradient, average solidification gradient and volumetric heat capacity of the chill used are important parameters controlling the soundness of aluminum-4.5% copper alloy plate, cylindrical and bar shaped castings.

1–10 of about 1210 matches for copper alloy
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