Revealing new depths of information with indentation mapping of microstructures.

Abstract

Nanoindentation is crucial in materials science for assessing mechanical properties in submicrometer volumes, and high-speed nanoindentation mapping has evolved it from a localized measurement technique into a scanning-probe-like approach for microstructures, delivering large-area, high-resolution mechanical property maps with more than 200,000 indents in hours. Such mapping enables direct imaging of hardness and modulus variations, phase boundaries, and local deformation behaviors in materials where heterogeneity governs mechanical performance. By correlating these mechanical maps with composition, orientation, and phase data from complementary analytical techniques, deep multidimensional data sets reveal the complex interplay between structure, processing, and properties. Such data sets increasingly demand advanced statistical clustering, machine learning, and deep learning for classification, trend extraction, and phase identification. Moving forward, high-speed nanoindentation is anticipated to operate under operando conditions and advanced mechanical modalities, offering new insights into interfacial deformation, anisotropic behavior, and the broader challenges of materials design and performance.

Graphical abstract: Schematic representation of high-speed nanoindentation mapping revealing microstructural heterogeneities in mechanical response. The indenter tip rapidly probes the surface, generating property maps sensitive to features such as twinning, recrystallization, segregation, precipitates, and sintered phases. These mechanical maps can be directly correlated with crystallographic and phase information from Electron Backscatter Diffraction (EBSD) and elemental composition from Energy-Dispersive X-ray Spectroscopy (EDS). Measurements can be performed operando, i.e., under real-time and service-relevant environmental conditions (e.g., temperature, atmosphere), enabling direct analysis of structure-property-performance relationships at the microstructural scale.