Need of an Inert Atmosphere for High-Energy Ball Milling of Al Alloys

This article compares the corrosion behavior and hardness of an Al alloy (AA2024) produced by high-energy ball milling in air and high-purity Ar. The pre-alloyed AA2024 powder was milled in Ar and air atmospheres, and the produced powder was successfully consolidated to investigate the hardness and corrosion performance. Cyclic potentiodynamic polarization tests revealed higher pitting potential for the alloy milled in air. Additionally, milling in air resulted in higher hardness and thermal stability after a 1-h isothermal heat treatment at 400 and 500 degrees C. Our results demonstrate that a high-purity Ar atmosphere is not a requirement for all applications and milling in the air can lead to excellent properties.