Multiple principal element alloys, also often referred to as compositionally complex alloys or high entropy alloys, present extreme challenges to characterize. They show a vast, multidimensional composition space that merits detailed investigation and optimization to identify compositions and to map the composition ranges where useful properties are maintained. Combinatorial thin film material libraries are a cost-effective and efficient way to create directly comparable, controlled composition variations. Characterizing them comes with its own challenges, including the need for high-speed, automated measurements of dozens to hundreds or more compositions to be screened. By selecting an appropriate thin film morphology through predictable control of critical deposition parameters, representative measured values can be obtained with less scatter, i.e., requiring fewer measurement repetitions for each particular composition. In the present study, equiatomic CoCrFeNi was grown by magnetron sputtering in different locations in the structure zone diagram applied to multinary element alloys, followed by microstructural and morphological characterizations. Increasing the energy input to the deposition process by increased temperature and adding high-power impulse magnetron sputtering (HiPIMS) plasma generators led to denser, more homogeneous morphologies with smoother surfaces until recrystallization and grain boundary grooving began. Growth at 300 °C, even without the extra particle energy input of HiPIMS generators, led to consistently repeatable nanoindentation load–displacement curves and the resulting hardness and Young’s modulus values.
The microstructure and local micromechanical properties of a Ni-based superalloy thin film produced by magnetron sputtering using ERBO/1 sputter targets were investigated. The thin film consists of columnar nanograins (an average size of ~ 45 nm) with mostly < 111 > orientation. Inside the nanograins, very fine nanotwins with an average thickness of ~ 3 nm are present. In-situ micropillar compression tests, complemented by nanoindentation, were conducted to evaluate the mechanical characteristics. The microhardness and Young’s modulus of the thin film correspond to ~ 11 and 255 GPa, respectively, the critical strength to ~ 4 GPa. The plastic deformation of the micropillars occurs through the formation of a shear band initiating at the top of the pillar. Inside the shear band, globular grains with random orientation form during the deformation process, while the regions near to the shear band remained unaffected.
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