Cover Image, Volume 11, Issue 1

Cover Photograph : ( Top Left ) The polarization optical microscope images show the formation of crystalline microarchitectures in Na ₂ Mn _0.9 Fe _0.1 P ₂ O ₇ glass formed by laser irradiation. Formed crystal is one of the promising cathode active materials for sodium‐ion batteries. There are two structural polymorphs (beta‐ and layered‐ ) and can selectively form either of them according to the power of laser irradiation. Honma et al. DOI: 10.1111/ijag.14102 . ( Bottom Right ) The apparent indentation fracture toughness of the silver and enamel layers deposited onto a glass substrate have been evaluated via SEM and high resolution surface topography images of the hardness imprints. The imprints are generated by nano‐indentation technique using a cube‐corner indenter. The determination of the fracture toughness by indentation consists in measuring the lengths of the cracks at the corners of the hardness impression. The absence of radial‐median cracks at the indents performed onto sintered silver provides clear evidence of the higher fracture toughness compared to enamel and glass, but prohibits a quantitative comparison. The soda‐lime silicate glass substrate has a homogeneous microstructure ensuring high repeatability onto the radial‐median cracks lengths resulting from the indentation. The average fracture toughness of the enamel layer is relatively complex to assess due to the multiphase microstructure. Walch and Roos DOI: 10.1111/ijag.13875 . image