This experiment is about Precipitation Aging of Aluminum alloys. There are three process: Solution heat treatment, Quenching, and Aging. Precipitation Aging increase strength and hardness for Aluminum alloys (2xxx, 6xxx and 7xxx). Two types of aging are natural aging & Artificial aging. The experiment study the relationship between the time to aging and stiffness measured (Brinell Hardness) to find the values that are the maximum rigidity.