6061 Aluminum is the most commonly used Aluminum Alloy. 6061 is highly rated for strength, almost twice that of 6063 and is generally used for structural applications where material strength is a significant factor. 6061 Aluminum is heat treatable and easy to machine and weld. The main alloy ingredients of 6061 aluminum are magnesium and silicon. 6061 Aluminum angle has radiused corners, as opposed to the sharp corners of 6063.