Effects of Interactions Among Alloying Elements on the Microstructure, Phase Transitions, and Electrical Resistivity of the Cu81Al19 Alloy

Cu-Al alloys have been used for marine applications due to their corrosion resistance and smart materials based on the shape memory effect. A technological tendency for Cu-Al alloys is the development of increasingly complex formulations, although the role of alloying elements still unclear in comparison to other metallurgical systems, such as steels. In the present study, 2 at% Cu were substituted by equal quantities of Ni and Ga in the Cu81Al19 alloy, which are elements from the same period and similar in size to the Cu atom. The obtained alloys were analyzed by several characterization techniques. The results showed that the Ni addition increases the critical temperatures and decreases the microhardness values. The Ga addition has the opposite effect. Both alloying elements produce new phases in the microstructures, hamper the alpha phase ordering, accelerate the beta phase decomposition, and increase the conductivity of the Cu81Al19 alloy. From this study, it is possible to realize that small changes in atomic features (electronic structure, atomic radius, valence, electronegativity) from a portion of atoms are enough to obtain distinctive materials, which turns the design of new Cu-Al alloys and the prediction of their properties a challenging task.

Automated summary

Cu-Al alloys are used in marine applications for their corrosion resistance and smart materials properties. The addition of Ni and Ga in Cu81Al19 alloy showed opposite effects on critical temperatures, microhardness values, and conductivity, leading to the formation of new phases in the microstructure. This study highlights how small changes in atomic features can significantly impact the properties of Cu-Al alloys.