Texture of magnesium alloy films growth by physical vapour deposition (PVD)

Abstract

The texture developed by four physical vapor deposited Mg alloys grown at two collector temperatures and their correlation with the microstructure have been studied. The alloys Mg–2.3Zr, Mg–10.6Zr and Mg–12Ti (wt%) deposited at around 150°C exhibited elongated grains growing in the normal direction to the deposit surface, but tilted with respect to the Z axis, with pores and cracks at the boundaries. A strong fibre texture of the ( 0001) basal plane component forming the fibre axis and the normal to the substrate plane an angle of 24, 18 or 12° depending on alloying element concentration has been found. The Mg–14Ti–1Al–0.9Mn (wt%) alloy, deposited at higher temperature, consisted of a region of columnar grains growing from the collector side followed by a thin region of equiaxed grains. Furthermore, a fibre texture with two components, the ( 0002) basal plane and the ( 112̄0) and the ( 101̄0) components in the collector and free surfaces, respectively, were present. Differences found in this alloy with respect to the alloys deposited at lower temperature were related to the surface diffusion phenomenon of adatoms caused by a higher collector temperature. The change in the second texture component from the collector to the free surface can explained by the decrease in the deposit strain energy.