New Quaternary MAX Phase Thin Films: Understanding the Thermally Induced Microstructural Evolutions and Reaction Mechanisms in Nanostructured Multilayers via Experimental Combinatorial Study
Final Report Abstract
Mn+1AXn (MAX) phases are nanolaminated compounds that possess remarkable and unusual properties combining attributes of both metals and ceramics. Multi-element alloying strategy offers further degrees of compositional and structural control to increase their chemical versatility and expand their physical and chemical properties. Double transition metal alloying to synthesize quaternary (M1M2)n+1AXn phases have resulted in the discovery of many new solid solutions and ordered phases (including out-of-plane ordering and in-plane ordering in M- layers). Intensive efforts have been implemented to explore new approaches for synthesizing high-quality ternary MAX phase thin films, but synthesis of quaternary MAX phase thin film materials has been rarely explored yet. This project focus on synthesis and structure/properties characterization of quaternary (M1M2)n+1AXn thin films in three different systems, i.e. Cr-M2-Al-C with M2: V, Ti, Zr, via thermal annealing of nanoscale multi-layered thin film precursors. These material systems cover all three types of chemical ordering on M-layers: random solid solution (CrxV1-x)2AlC (0 < x < 1), out-of-plane ordered (Cr2/3Ti1/3)3AlC2, and in-plane ordered (Cr2/3Zr1/3)2AlC. The multi-layered thin film precursors with pre-defined nanostructured architectures and varied chemical compositions comprising large fractions of Cr - M2 binary systems were deposited by combinatorial magnetron sputtering using segmented transition metal targets or CrM2 alloy targets, and pure graphite and Al targets. To resolve the path from the multi-layered precursors towards the desired quaternary MAX phase formation with respect to phase transformations, microstructural evolutions, and underlying reaction mechanisms, in-situ high-temperature X-ray diffraction (HT-XTD) and thorough compositional and microstructural analyses at the nanoscale, combing high-resolution scanning transmission electron microscopy (HR-STEM) and atom probe tomography (APT), were performed. Solid solution (CrxV1-x)2AlC and out-of-plane ordered (Cr2/3Ti1/3)3AlC2 were successfully synthesized after annealing at specific temperatures, while annealing of the multi-layered precursors in the Cr-Zr-C-Al system mainly resulted in the formation of ternary MAX phases and binary compounds. The reaction pathways and reaction mechanisms of whether complex quaternary MAX phases formation in the three different systems have been comparatively studied, which provides guidelines on designing nanostructured multilayer precursors and defining thermal treatment procedures for synthesizing high-quality quaternary MAX phase thin films. In addition, thermal stability, high-temperature oxidation resistance, and mechanical properties of selected quaternary MAX phase films have been documented, which serves as a valuable resource for choosing suitable alloying strategies to tailor their properties to meet the requirements of various advanced applications.
Publications
-
Corrosion behavior of Al-containing MAX-phase coatings exposed to oxygen containing molten Pb at 600°C. Corrosion Science, 201, 110275.
Shi, Hao; Azmi, Raheleh; Han, Liuliu; Tang, Chongchong; Weisenburger, Alfons; Heinzel, Annette; Maibach, Julia; Stüber, Michael; Wang, Kangli & Müller, Georg
-
The Effect of Annealing Temperature on the Microstructure and Properties of Cr–C–Al Coatings on Zircaloy-4 for Accident-Tolerant Fuel (ATF) Applications. Coatings, 12(2), 167.
Tang, Chongchong; Steinbrück, Martin; Grosse, Mirco; Ulrich, Sven & Stüber, Michael
-
Synthesis of V2AlC thin films by thermal annealing of nanoscale elemental multilayered precursors: Incorporation of layered Ar bubbles and impact on microstructure formation. Applied Surface Science, 629, 157340.
Tang, Chongchong; Dürrschnabel, Michael; Jäntsch, Ute; Klimenkov, Michael; Steinbrück, Martin; Ulrich, Sven; Hans, Marcus; Schneider, Jochen M. & Stüber, Michael
