yielding and irreversible deformation below the microscale surface effects and non-mean-field plastic avalanches收益率和不可逆转的变形在微尺度表面效果和non-mean-field塑料雪崩.pdfVIP

Yielding and Irreversible Deformation below the Microscale: Surface Effects and Non-Mean-Field Plastic Avalanches Paolo Moretti1,2*, Benedetta Cerruti1,3, M.-Carmen Miguel1 ´ ´ ´ ` 1 Departament de Fısica Fonamental, Facultat de Fısica, Universitat de Barcelona, Barcelona, Spain, 2 Departament de Fısica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Barcelona, Spain, 3 Institute for Cancer Research and Treatment, Candiolo, Turin, Italy Abstract Nanoindentation techniques recently developed to measure the mechanical response of crystals under external loading conditions reveal new phenomena upon decreasing sample size below the microscale. At small length scales, material resistance to irreversible deformation depends on sample morphology. Here we study the mechanisms of yield and plastic flow in inherently small crystals under uniaxial compression. Discrete structural rearrangements emerge as a series of abrupt discontinuities in stress-strain curves. We obtain the theoretical dependence of the yield stress on system size and geometry and elucidate the statistical properties of plastic deformation at such scales. Our results show that the absence of dislocation storage leads to crucial effects on the statistics of plastic events, ultimately affecting the universal scaling behavior observed at larger scales. Citation: Moretti P, Cerruti B, Miguel M-C (2011) Yielding and Irreversible Deformation below the Microscale: Surface Effects and Non-Mean-Field Plastic Avalanches. PLoS ONE 6(6): e20418. doi:10.1371/journal.pone.0020418 Editor: Matteo Rini, Joint Research Centre - European Commission, Germany Received February 11, 2011; Accepted April 29, 2011; Published June 7, 2011