Nanomechanics of Mg-Gd-Y-Nd-Zn alloy with LPSO and MgRE phases
H. Vafaeenezhad, S. Aliakbari-Sani, A. Kalaki, G.R. Ebrahimi, Jürgen Hirsch
Abstract
• A new method through nanoindentation using a Berkovich indentor coupled with numerical simulation is suggested for characterizing the elastic–plastic behavior of materials within micro/nanoscale. • Plastic deformation pattern of all phases in the studied Mg alloy is characterized by obtaining strain hardening rate and coefficient based on the force–depth graph and indentation pileup profiles. • The measurement of fracture toughness of all constituent phases was done by use of energy-based microscale cracking approach and nanoindentation data. The mechanical properties of two main precipitating phases (LPSO and MgRE) and matrix in Mg-Gd-Y-Nd-Zn bioalloy were examined using nanoindentation method. A new is suggested for characterizing the elastic–plastic behavior, fracture toughness and strain rate sensitivity (SRS) of materials within micro/nanoscale. Firstly, a nanomechanical model was developed for extracting hardness (H), young's modulus (E) and yield stress (σ Y ) from the characteristic load points which were subsequently analyzed by atomic force microscope (AFM) images. The elasticity data and AFM data were then utilized for determination of plastic deformation in constituent phases. The displacement of the indentation gets the highest value for Mg matrix and between precipitates, depth is more in LPSO rather than that of MgRE. The serrated flow or the behavior of shear bands may originate from the side effect of the interface region in Mg alloys with precipitates. It can be deduced that the KIC produced by both L method and energy-based calculation are both reliable for K IC approximation. The maximum load in simulation with µ=0.2 friction is marginally lesser than that of the frictionless (µ=0) one while elastic recovery of indentation with µ=0.2 is higher to some extent.