20.500.12556/DKUM-84738 Evolution of chemically induced cracks in alkali feldspar: thermodynamic analysis A system of edge cracks was applied to polished (010) surfaces of K-rich gem-quality alkali feldspar by diffusion-mediated cation exchange between oriented feldspar plates and a Na-rich NaCl–KCl salt melt. The cation exchange produced a Na-rich layer at and beneath the specimen surface, and the associated strongly anisotropic lattice contraction lead to a tensile stress state at the specimen surface, which induced fracturing. Cation exchange along the newly formed crack flanks produced Na-enriched diffusion halos around the cracks, and the associated lattice contraction and tensile stress state caused continuous crack growth. The cracks nucleated with non-uniform spacing on the sample surface and quickly attained nearly uniform spacing below the surface by systematic turning along their early propagation paths. In places, conspicuous wavy cracks oscillating several times before attaining their final position between the neighboring cracks were produced. It is shown that the evolution of irregularly spaced towards regularly spaced cracks including the systematic turning and wavyness along the early propagation paths maximizes the rate of free energy dissipation in every evolutionary stage of the system. Maximization of the dissipation rate is suggested as a criterion for selection of the most probable evolution path for a system undergoing chemically induced diffusion mediated fracturing in an anisotropic homogeneous brittle material. chemically induced fracturing alkali feldspar crack spacing wavy cracks dissipation rate thermodynamic extremal principle kemično povzročeno lomljenje alkalni feldspar razmik razpok valovite razpoke stopnja disipacije termodinamično ekstremno načelo true false true Angleški jezik Slovenski jezik Neznano 2023-07-17 12:50:28 2023-07-17 12:50:28 2023-07-18 03:08:12 0000-00-00 00:00:00 2022 0 0 15 str. art. no. 14 Vol. 49 May 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2022-05-01 539.3 106807299 10.1007/s00269-022-01183-9 1432-2021 RAZ_Abart_Rainer_2022.pdf RAZ_Abart_Rainer_2022.pdf 1 7A09D6C934EFF60EF404ED2B5D716A59 bc2d3bf745b87821be79a124ab92384ef2ec7308d5fb39bf3559a7ae9f059cf6 15c2de68-2490-11ee-8abb-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=168809 https://link.springer.com/article/10.1007/s00269-022-01183-9 0 231a6938-2490-11ee-8abb-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=168810 Fakulteta za strojništvo 0 0 0