Crystal-chemistry control of the mechanical properties of 2:1 clay minerals

摘要: Abstract Clay minerals are the main constituents of clay matrix a wide variety sedimentary deposits. When subjected to burial, some these undergo phase transitions accompanied by atomic substitutions which ultimately impact cohesive interactions between their constitutive layers. The most common among such is smectite illitization, also highly relevant for oil and gas exploration production from source rocks. this transition on mechanical properties as well bearing rocks remains, however, be properly addressed. To end, set macroscopic single 2:1 (pyrophyllite, talc, vermiculite, phlogopite, muscovite, clintonite) representative two octahedral fillings variation in surface charge densities was investigated. A hybrid experimental-modeling approach proposed, combines nanoindentation orthogonal directions (x1 x3-directions) with analytical derivations energy (Ui) using XRD TEM-EDS measurements. results highlight that interlayer defines elasticity (modulus M), strength (hardness H) ductility behavior (M/H) materials; not bond stored into constituent This finding permits derivation predictive stiffness functional relations derivatives account arrangement nanoscale layers composition. These suggest cohesion increases coulombic through progressive system loses its capacity dissipate applied dislocation mechanisms layers, entailing an increase brittleness particles burial. By way conclusion, geophysics geochemistry implications predicting performance geomaterials, economically valuable rocks, discussed.