Structure and thermal decomposition of a nanocrystalline mechanically alloyed supersaturated Cu-Ta solid solution

The formation of a metastable Cu-Ta solid solution in a mechanically alloyed Cu-10 at.% Ta alloy and its subsequent decomposition during annealing was investigated by atom probe tomography. During annealing, the as-milled Cu-rich alloy undergoes phase separation; Ta atoms diffuse out of the Cu lattice to form Ta clusters and particles along grain boundaries and within the Cu grains. The role of the Ta clusters and the nature of the solid solution as a potential strengthening mechanism for these alloys are discussed.