Chapters authored
Improving Contact Load-Bearing Resistance of Ultrafine- Grained Materials Through Multilayering and Grading
Structural multilayering and grading has been designed to improve the contact load-bearing resistance of ultrafine-grained materials. The contact load-bearing response and surface damage resistance of multilayered hierarchical structured (MHSed) Ti were evaluated by experimental indentation on the overall loading response in conjunction with detailed computational simulations of local stresses and strain distribution. The combination of a hard outer layer, a gradual transition layer and a compliant core results in reduced indentation depth, but a deeper and more diffuse sub-surface plastic deformation zone, compared to the monolithic nanostructured Ti. The macroscopic indentation resistance of MHSed Ti is controlled by the underlying micromechanics of the multilayered hierarchical structure. The finite element analysis (FEA) revealed the multilayered hierarchical structure offers the effective macroscopic mechanical contact loading resistance, where the indenter increasingly “senses” the more compliant core to bear the deformation as the load increases. The structural multilayering modifies the stress and strain redistribution and effectively reduces the maximum stress concentration within the material. The structural grading provide a transitional junction for stress and plastic deformation redistribution and achieve more gradual stress distributions between component layers which mitigates the interface failure, increases the interfacial toughness, thus providing strong resistance to loading damage.
Part of the book: Contact and Fracture Mechanics