Thermal stability of sputtered Cu/304 stainless steel multilayer films

We report on the thermal stability of sputter-deposited Cu/304 stainless steel nanoscale multilayer films. For individual layer thickness of approximately 70 nm, the layered morphology was stable up to 600 degrees C with no significant change in the hardness. The stainless steel layer had a duplex bcc+fcc structure that was also preserved in annealed films. After annealing at temperatures of 650 degrees C or higher, the hardness of these multilayer films decreased from 4.75 to 3.4 GPa due to morphological evolution from layers to equiaxed grains and coarsening of the nanolayers. (c) 2007 American Institute of Physics.