Aluminum is
the alloy of choice for weight savings, but the performance requirements and
manufacturability issues will drive the choice of a specific aluminum alloy.
- For mechanical performance, the aluminum alloy has to be both strong and tough, because
brittle fracture in a brake pedal is unacceptable in a fracture critical part.
- GM engineers set mechanical specifications of 35 ksi ultimate tensile strength, 25 ksi
tensile yield strength, and 7% elongation.
- The brake pedal has to maintain its surface appearance in a wide variety of
environments. Corrosion of the aluminum has to be minimized.
From the casting perspective, the long, narrow
geometry of the brake pedal requires an aluminum alloy that will flow and fill the mold
easily, but will not solidify too quickly. Rapid solidification can produce cracks (hot
tearing) in the casting |
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