Coupling effects of W alloying with preparation temperature on microstructures and irradiation tolerance of nanostructured Cu films

Grain size is a critical factor determining materials properties but is challenging to be quantitatively controlled especially in nanoscale. Here, we found the average grain size of pure Cu film can be enhanced from 23 to 557 nm with the preparation temperature increasing from 298 to 773 K during magnetron sputtering. The temperature effect is weakened after W addition to Cu matrix and the grain size of Cu96W4 samples just exhibits slight increase from 30 to 145 nm. The coupling effect of W alloying with temperature is related to the decreased diffusion of Cu atoms after W addition during magnetron sputtering process. Cu-W supersaturated solid solution is formed at low temperatures (below 773 K for Cu96W4 or 573 K for Cu94W6) but W atoms could be agglomerated at elevated temperatures. Moreover, after He ions irradiation at 673 K, fewer and smaller cavities are formed in Cu96W4 samples compared to pure Cu, indicating that W addition could significantly enhance irradiation tolerance.

Automated summary

Grain size is a critical factor in determining the properties of materials, but it is difficult to control quantitatively, especially at the nanoscale. By increasing the preparation temperature during magnetron sputtering, the average grain size of pure Cu film can be enhanced from 23 to 557 nm. However, the temperature effect is weakened after adding W to the Cu matrix, with only a slight increase in grain size from 30 to 145 nm for Cu96W4 samples. The addition of W affects the diffusion of Cu atoms during the magnetron sputtering process, forming a Cu-W supersaturated solid solution at low temperatures but causing W atoms to agglomerate at elevated temperatures. Furthermore, W addition significantly enhances the irradiation tolerance, leading to the formation of fewer and smaller cavities in Cu96W4 samples compared to pure Cu after He ions irradiation at 673 K.