Effects of deposition parameters on residual stresses, hardness and electrical resistivity of nanoscale twinned 330 stainless steel thin films

We have explored the influence of sputtering parameters on the structural, mechanical, and electrical properties of nanoscale twinned 330 stainless steel thin films. As the residual stress in the film is changed from tensile to compressive by varying the growth conditions, the nanoscale twinned structure, the average columnar grain size and texture of the film show little or no change. Hardness of the film in compression reaches 7 GPa, compared to about 5.5 GPa in films with high residual tension, and an order of magnitude higher than that of bulk 330 stainless steel. Molecular dynamics simulations indicate that twin boundaries pose a strong barrier to glide dislocation transmission under applied in-plane biaxial loading, consistent with the GPa level strengths measured in these films. The increase in the room temperature electrical resistivity of these films, compared to bulk 330 stainless steel, is found to be small, indicating that nanoscale twinned structures may provide the best combination of high mechanical strengths and high electrical conductivity. (C) 2005 American Institute of Physics.