Paper Type |
Contributed Paper |
Title |
Combined Effects of Boron, Sodium and Strontium on Grain Refi nement of Sterling Silver Grade 950 |
Author |
Siriwan Sakultanchareonchai*[a], Torranin Chairuangsri [b] and Ekasit Nisaratanaporn [a] |
Email |
sakultan@gmail.com |
Abstract: Combined effects of B, Na and Sr on grain refi nement of sterling silver grade 950 were investigated. The silver alloys with different composition of B, Na and Sr were prepared in three steps including pre-alloy preparation, master alloy preparation and fi nally sterling silver casting. Characterization was performed by inductively coupled plasma – optical emission spectroscopy for determining chemical composition, and light microscopy, scanning electron microscopy and electron probe microanalysis for investigating microstructure. The tensile properties of the alloys were determined following the ASTM E 8M-96. The results revealed that micro-scale addition of B, Na and Sr plays a signifi cant role in grain refi nement. Effective grain refinement with bright surface appearance, no hot tearing crack and almost no micro-shrinkage can be achieved. The mechanism of grain refi nement by combined effects of B, Na and Sr is yet to be understood, but it cannot be related to the distribution of micro-scale second phase. The highest ultimate tensile strength of the alloy achieved was about 178 MPa, nearly twice of that of the typical sterling silver alloy (about 90 MPa). This confi rms advantages of the grain-refi ned alloy on jewelry application.
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Start & End Page |
370 - 379 |
Received Date |
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Revised Date |
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Accepted Date |
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Keyword |
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Volume |
Vol.38 No.3 (JULY 2011) |
DOI |
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Citation |
Sakultanchareonchai S., Chairuangsri T. and Nisaratanaporn E., Combined Effects of Boron, Sodium and Strontium on Grain Refi nement of Sterling Silver Grade 950, Chiang Mai J. Sci., 2011; 38(3): 370-379. |
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