MSE 3331 Mod 2 Whale Sharks Instructions for 7037-T7 Aluminum Alloy

Aluminum alloy 7037 was cast and underwent homogenization, thermomechanical processing, solution heat treating, and aging in order to maximize yield strength, elongation, and conductivity testing.

Step 1: Weigh Samples

Weigh the intended weight for each element being added to the melt, based on the weight percent for each element in a 7037 alloy.

Goal Composition: 89% Al (890g), 1% Cu (10g), 2% Mg (20g), 8% Zn (80g)

Actual Composition: 890.05g Al (449.0g Al block, 3.15g Al foil, 437.9g Al pellets), 10.11g Cu, 20.45g Mg, 80.39g Zn

Actual composition is what is represented in all pictures and results.

Step 2: Begin Melting

Since Aluminum is the bulk of the alloy, it needs time to melt before the rest of the elements, place the weighed samples in the induction furnace, and raise the temperature to (insert temperature) degrees Celsius. After the aluminum is fully melted, add the Copper, Magnesium, and Zinc in that order, stirring in each addition with a metal rod to ensure the elements have mixed thoroughly.

Step 3: Pour

The mold for the alloy should be heated using a blow torch to remove any moisture. Once the alloy has been heated long enough to melt all the additions, turn off the furnace and put on a Kevlar jacket and hood. Carefully grab the crucible from the furnace using circular prongs, and hold the crucible using the top lip, not by squeezing the prongs around the body. Quickly pour the alloy into the mold until it is full, without spilling too much of your content. Once the mold is full, pour any remaining liquid into a separate mold for extra material.

Step 4: Homogenization

The cooled alloy block now needs to undergo homogenization. Place alloy in oven set at 475 degrees Celsius and remove after 5 hours. Make sure to set homogenized alloy on a heat safe surface to cool completely before continuing onto the next step.

Step 5: Mechanical Processing

Hot roll the sample at 450 degrees Celsius to a 75-80% reduction to around 3mm thick. Once the furnace has reached 450 degrees Celsius push the sample into the furnace. After the material has also reached 450 degrees Celsius push it through the rolling mill and repeat. Make sure the same rolling direction is used each time. Then, once the material is near the desired thickness, cold roll at room temp to achieve a final thickness of 2.5 mm for tensile bars.

Step 6: Solution Heat Treating and Aging

Solution heat treat the material at 480 degrees Celsius for 2 hours, before quenching in cold water for about 10 seconds. Now the sample needs to be aged using a one-step process at 160 degrees Celsius for 10 hours.

Step 7: Testing

Properties such as yield strength, electrical conductivity, and elongation can be measured. The measurements should be recorded in MPa, %IACS, and percent elongation respectively. First, the alloy needs to be cut into tensile bars from the block of material. Then load the sample into the machine and attach it to the extensometer. This will measure the percent elongation and yield strength. Then using a metal conductivity meter the electrical conductivity can be measured.