Changes in the hardness of age hardenable aluminum and titanium alloys are typically accompanied by changes in what?

In age-hardenable aluminum and titanium alloys, changes in hardness are closely associated with variations in conductivity. This relationship arises because, during the aging process, the microstructure of the alloy evolves, affecting the arrangement and interactions of atoms and phases within the material. As the hardness increases due to the formation of precipitates and other microstructural changes, there is often a corresponding decrease in electrical conductivity. This phenomenon occurs because the densification and dislocation structures that contribute to strengthening also impede the flow of electrical current, thus reducing conductivity.

Conductivity is essential in applications where electrical performance is critical, and understanding how it is influenced by changes in hardness can help in optimizing materials for specific uses. Therefore, as the hardness of these alloys increases through age hardening, monitoring changes in conductivity provides insights into their performance characteristics and suitability for particular engineering applications.