Metallographic Investigations of Silver Alloys Used for Minting

2017 ◽  
Vol 891 ◽  
pp. 89-94 ◽  
Author(s):  
Stephanie Greil ◽  
Christian Edtmaier ◽  
Roland Haubner ◽  
Lukas Lauter
Keyword(s):  
Mechanical Properties ◽  
Chemical Etching ◽  
Cold Working ◽  
Copper Alloys ◽  
Micro Hardness ◽  
Pure Silver ◽  
Mechanical Grinding ◽  
Silver Alloys ◽  
Silver Copper ◽  
Metallographic Preparation

A typical metallographic preparation (i.e. mechanical grinding and chemical etching) and electrochemical etch-polishing was carried out to observe the microstructure of pure silver and two silver-copper alloys (Sterling silver Ag 925 and Ag 333) in circular blanks used for coin production. The obtained micrographs revealed cold working effects on the coin rim caused by the rimming process. These rim effects are the reason for local differences in the mechanical properties of circular blanks, posing a challenge to tool lifetime. To quantify these effects, a micro hardness-mapping was performed and analysed.

scholarly journals I. The liquation of gold and platinum alloys

1890 ◽  
Vol 47 (286-291) ◽  
pp. 180-186 ◽  
Keyword(s):  
Copper Alloys ◽  
Gold Alloys ◽  
Silver Alloys ◽  
Platinum Alloys ◽  
Silver Copper ◽  
Gold Silver ◽  
Almost All

It is a well known fact that when molten alloys of certain metals are cooled, some of the constituents separate and become concentrated either in the centre or in the external portions of the solidified mass; to this segregation the name of liquation is given. It is specially noticeable in the case of silver-copper alloys, and its importance is now being widely recognised in almost all branches of metallurgy. In the case of gold, however, the phenomenon of liquation does not appear to have been much observed. Gold alloys, to the value of many millions sterling, pass annually from hand to hand upon the results of assays cut from the external portions of ingots, which assays cannot, of course, be trustworthy, if the centre of the bars differs in composition from the external portions. Peligot has recently endeavoured to obtain evidence of liquation in gold-copper alloys, and has concluded that it does not exist. Roberts-Austen, who has devoted much time to the study of liquation, has also satisfied himself that gold-silver alloys do not rearrange themselves on cooling.

Mechanical Properties of Chemical Etched Biomedical NiTi Alloy Wires

2009 ◽  
Vol 417-418 ◽  
pp. 941-944
Author(s):  
Zhen Li ◽  
Zhao Qing Li ◽  
Li Da Hou ◽  
Li Li
Keyword(s):  
Mechanical Properties ◽  
Chemical Etching ◽  
Niti Alloy ◽  
Side Surface ◽  
Hardness Test ◽  
Tensile Tests ◽  
Etching Process ◽  
Phase Identification ◽  
Micro Hardness ◽  
Niti Wires

Nickel-titanium alloy wires are widely applied in manufacturing biomedical devices; however, it is difficult to be micro-fabricated. Chemical etching process can successfully micro-fabricate the Ni-Ti alloy. The surface morphology, the etching products and the mechanical properties of the fine NiTi wires after the chemical etching process are investigated in the paper. After etching process, the characteristics of the wire surface are studied by Scanning Electron Microscopy (SEM). The X-Ray Diffraction (XRD) phase identification analysis is used to identify the etching products on the side surface of the etched wire. The Vickers Micro-hardness Test shows that the micro-hardness in peripheral surface is slightly higher than that in bulk. Mechanical properties of NiTi alloy fine wires after etching were studied by means of tensile tests.

scholarly journals Effect of Rare-Earth Metals Addition on Microstructure and Properties of Selected Copper Alloys

2014 ◽  
Vol 59 (2) ◽  
pp. 641-648 ◽  
Author(s):  
Z. Rdzawski ◽  
W. Głuchowski ◽  
J. Stobrawa ◽  
J. Sobota
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Cold Working ◽  
Copper Alloys ◽  
Rare Earth Metals ◽  
Tension Test ◽  
Metal Working ◽  
Electron Backscattered Diffraction ◽  
Microstructure And Properties ◽  
Scanning Electron

Abstract Effect of addition of rare earth metals on microstructure and properties of copper alloys after casting, after cold working and after heat treatment was studies in this paper. Methodology consisted of microstructure investigations by optical microscopy and scanning electron microscopy. In addition, distribution of alloying elements and electron backscattered diffraction results (EBSD) were presented. The mechanical properties of a wire after tension test and after hardness measurements were described. Electrical conductivity test was performed using Foerster Sigmatest and Thomson bridge. Analysis of the microstructure and mechanical properties of investigated alloys after casting and after metal working showed possibility to produce materials with preferred set of functional properties.

CARLSON ALLOY C600 and C600 ESR

Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Cold Working ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Solid Solution Alloy ◽  
Resistance To Oxidation ◽  
Good Workability

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.

ALLEGHENY LUDLUM TYPE 205

Alloy Digest ◽  
1997 ◽  
Vol 46 (10) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Magnetic Permeability ◽  
Cold Working ◽  
High Strength ◽  
Heat Treating ◽  
Austenitic Steels

Abstract Allegheny Stainless Type 205 is a chromium-manganese nitrogen austenitic high strength stainless steel that maintains its low magnetic permeability even after large amounts of cold working. Annealed Type 205 has higher mechanical properties than any of the conventional austenitic steels-and for any given strength level, the ductility of Type 205 is comparable to that of Type 301. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SS-640. Producer or source: Allegheny Ludlum Corporation. Originally published March 1996, revised October 1997.

Micro-Hardness and Morphology of LDPE Influenced by Beta Radiation

2014 ◽  
Vol 606 ◽  
pp. 253-256 ◽  
Author(s):  
Martin Ovsik ◽  
Petr Kratky ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hardness Test ◽  
Polymer Materials ◽  
Beta Radiation ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Depth Sensing ◽  
Surface Layers ◽  
Hardness Values ◽  
Different Doses

This article deals with the influence of different doses of Beta radiation to the structure and mico-mechanical properties of Low-density polyethylene (LDPE). Hard surface layers of polymer materials, especially LDPE, can be formed by radiation cross-linking by β radiation with doses of 33, 66 and 99 kGy. Material properties created by β radiation are measured by micro-hardness test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 66 and 99 kGy, when the micro-hardness values increased by about 21%. The changes were examined and confirmed by X-ray diffraction.

scholarly journals Numerical investigation of mechanical properties of aluminum-copper alloys at nanoscale

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Satyajit Mojumder ◽  
Md Shajedul Hoque Thakur ◽  
Mahmudul Islam ◽  
Monon Mahboob ◽  
Mohammad Motalab
Keyword(s):  
Mechanical Properties ◽  
Numerical Investigation ◽  
Copper Alloys ◽  
Aluminum Copper Alloys

Influence of Melt Temperature on Compressive Plasticity of a Cu-Zr-Al Bulk Metallic Glass

2010 ◽  
Vol 146-147 ◽  
pp. 517-521
Author(s):  
Sheng Hui Xie ◽  
Xie Rong Zeng ◽  
Dong Ju Fu ◽  
Lei Zhao ◽  
Qiang Hu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Mechanical Performance ◽  
Casting Temperature ◽  
Thermal And Mechanical Properties ◽  
Micro Hardness ◽  
Melt Temperature ◽  
Hardness Tests ◽  
Important Solution

Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) were cast from the melt temperature 1143 to 1373 K. The structure, thermal and mechanical properties of the BMGs were investigated by XRD, DSC, HRTEM, dilatometric measurements, micro-hardness tests and uniaxial compression. The results indicate that the microstructure and mechanical performance of BMGs are closely affected by the casting temperature. Proper casting temperature ensures the BMGs with large relaxed excess free volume (REFV) and nano-crystallites, which favor the plastic deformation in Cu47.5Zr47.5Al5 BMGs. Regulating the preparing parameters is an important solution to good plasticity in BMGs.

scholarly journals Experimental Evaluation of Mechanical Properties of Friction Welded Dissimilar Steels under Varying Axial Pressures

2016 ◽  
Vol 66 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Amit Handa ◽  
Vikas Chawla
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Failure Analysis ◽  
Friction Welding ◽  
Experimental Evaluation ◽  
Micro Hardness ◽  
Aisi 304 ◽  
Torsional Strength ◽  
Hardness Values

AbstractThe present study emphasizes on joints two industrially important materials AISI 304 with AISI 1021steels, produced by friction welding have been investigated. Samples were welded under different axial pressures ranging from 75MPa to 135MPa, at constant speed of 920rpm. The tensile strength, torsional strength, impact strength and micro hardness values of the weldments were determined and evaluated. Simultaneously the fractrography of the tensile tested specimens were carried out, so as to understand the failure analysis. It was observed that improved mechanical properties were noticed at higher axial pressures. Ductile failures of weldments were also observed at 120MPa and 135MPa axial pressures during fractography analysis.

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