Thermal aging and alloys
Our hypothesis that an alloy’s hardness will increase when aged at higher temperatures, is proven to be true only to a certain extent. When aged beyond a certain temperature, the alloys actually became softer.Steel is one of the most common alloys in the world and about 1.3 billion tons of steel is produced every year. It is used in building construction, ship building, automobile manufacturing, machines, tools and aircraft. Apart from improved hardness, steel is also more resistant to corrosion and it is also easier to weld. Steel is treated by aging at high temperatures over time to increase its hardness and toughness. However, heating the steel above a critical temperature will cause it to “anneal” and become softer
This science fair project can be modified to test the maximum aging temperature for different types of alloys.
Would aging for longer periods of time and compare the hardness of the alloys.
Alloy - http://en.wikipedia.org/wiki/Alloy
Steel - http://en.wikipedia.org/wiki/Steel
Information about hardness - http://www.performancealloys.net/Hardness%20Information.htm
Ensure that the experiment is conducted in a properly equipped laboratory, under the supervision of your science teacher. Hot metal samples need to be handled with the use of proper equipment and protective gear.