Mechanical Characterization Potentials of Aluminide Diffusion Coatings on Molybdenum Substrates

A mechanical test strategy is designed to determine the resistance of protective intermetallic aluminum layers on molybdenum substrates. Performing mechanical experiments, such as compression, four‐point bending and indentation tests, the specific failure behavior and a potential impact of observed phase transformations within the interface zone on the structural integrity and adhesion strength are examined. Herein, the applied test structure aims at the description of damage characteristics and critical deformation states regarding the type of loading. In this respect, it focuses on delamination behavior under compressive load and crack channeling due to bending stress. The analysis of the mechanical experiments is supported by various measurement techniques, including 3D camera equipment (GOM) and an acoustic emission (AE) analysis system. In particular, the application of the AE technique in this work provides a helpful contribution to the detection of delamination failure and the development of multiple crack channeling. Considering the successfully applied experimental approaches, it is assumed that more complex coating‐base material combinations can be characterized this way with respect to preceding annealing effects and the thereby influenced load capacity of thin films under different loading types.