Microstructural characterisation of TiAl thin films grown by DC magnetron co-sputtering technique

Abstract

The present study deals with the in situ growth of 〈111〉 oriented thin films of TiAl grown by co-sputtering from high purity Ti and Al targets in a DC magnetron sputtering system. The influence of substrate temperature on the chemical and microstructural changes occurring in TiAl thin films has been investigated in the substrate temperature range 573–873 K. Electron probe microanalysis shows that Al concentration increases from 55.78 to 62.15 at.%, while Ti concentration decreases from 44.22 to 37.85 at.% with increase in the substrate temperature. Atomic Force Microscopy (AFM) of the TiAl films indicates an increase in the crystallite size with substrate temperature. A fine globular morphology of crystallites with a mean surface area of ∼1850 nm² at 573 K changes to crystallites with a surface area of ∼2300 nm² at 773 K.