Saturday, February 25, 2012

The Marriage of 2 Metals...a long time ago

Hi All!  This Brush Wellman Technical Tidbit was emailed to me and I thought it would be a great resource for some.  So enjoy....and learn :)  And just to make sure to give credit where credit is due, this was written by Brush Wellman.

 Solid Solution Hardening & Strength
(April 2010 updated from October 2000 Publication) by Brush Wellman

Approximately five thousand years ago, early humans discovered they could make a strong, tough metal by mixing copper and tin together. They had created the world’s first Alloy (a mixture of two or more metals). Unaware at the time, they were taking advantage of an important strengthening mechanism, solid solution hardening. The Bronze age therefore became the dawn of metallurgy.

Solid solution hardening is simply the act of dissolving one metal into another, similar to dissolving sugar into coffee. This is done during casting, when all the metals involved are in liquid form. For electrical connectors, copper is usually the main ingredient and is said to be the solvent, similar to the coffee in the above example. Other elements, playing the role of the sugar, to be added to the copper are known as the solutes.

There is a limit to the amount of solute that can be dissolved in to the solvent. This is known as the solubility limit. For example, coffee will only dissolve so much sugar before the excess settles on the bottom. However, raising the temperature of the solvent can often increase the solubility limit. There are several thermal strengthening methods that depend on having excess solute cast into the material and frozen into place when the mixture cools. Read More ......

Written by Mike Gedeon of Brush Wellman's Alloy Customer Technical Services Department. Mr. Gedeon's primary focus is on electronic strip for the telecommunications and computer markets with emphasis on finite element analysis (FEA) and material selection. Mr. Gedeon can be reached via email at alloy_tech_svc@brushwellman.com or by phone at 1-800-375-4205.

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