Effect of Controlled Heat Treatment and Aluminum Additions on the Strengthening of Cu–Ni-Based Alloys

In this investigation, Cu–Ni alloys with different aluminum additions were synthetized under a vacuum atmosphere to reduce the material density. Annealed alloys in a He atmosphere with low aluminum concentration exhibited a coarse dendritic structure, while samples with high aluminum concentration exhibited a refined dendritic structure. Structural defects analyses have shown relatively low vacancy concentrations. Hardness evaluations indicated an increment by approximately 5 times i.e., 370 HVN, more than that for the alloyed samples compared with the as-cast and unalloyed samples. Compression tests have shown a noticeable strengthening improvement (360 MPa), mainly in samples heat treated with 10 at.% Al, while samples with 5 at.% Al showed an acceptable resistance (270 MPa) as well. In general, the sample with 10 at.% Al presented the best performance to be considered as potential structural material.