Published online by Cambridge University Press: 25 February 2011
Vapor phase synthesis approaches were employed to produce laminated microstructures with high temperature phases alternated with ductile phase layers for toughness enhancement. Microlaminates of alternating layers of Mo and cosputtered Mo-Si were deposited on a Si substrate using direct current (DC) and radio frequency (RF) sputtering technique. Microstructural evolution and phase formation after diffusion annealing (900°C, 2 hr) was evaluated using cross-sectional transmission electron microscopy (TEM). Heat treating the microlaminates resulted in the growth of a Mo3Si interface phase between Mo and cosputtered layer and conversion of the amorphous cosputtered layer into crystalline Mo5Si3. A higher Si/Mo ratio in the cosputtered layer caused the formation of dispersed Mo5Si3 grains in Mo layer. The residual stress state was measured by monitoring the curvature change of the microlaminates using a laser beam. By decreasing the bilayer thickness to 1/3, the residual stress is reduced by ∼50%.