Extracting HCP Zerilli-Armstrong material parameters for magnesium alloy AZ31B from orthogonal cutting tests

Abstract

This work reports on a methodology to extend Oxley's analysis of the thick shear zone to account for HCP materials. Ultimately, the work extracts Zerilli-Armstrong (ZA) constitutive equation’ material parameters for AZ31B, an HCP crystal structure magnesium-based alloy. The methodology for accomplishing this utilizes three tasks namely: 1) Extension of thick shear zone approach for machining force simulation to account for Zerilli-Armstrong HCP material model, 2) measure cutting and thrust edge forces from orthogonal cutting tests (uncut chip thickness and cutting speed values varying between 0.05 and 0.4 mm/rev and 50–400 m/min, respectively), and 3) numerically determine updated material model parameters for AZ31B by minimizing the difference between the methodology-predicted forces and those experimentally measured. Comparing numerical data with the experiments, the determined AZ31B material model with updated parameters yielded predictability of R2 of 0.94 and 0.91 for cutting and thrust forces, respectively. Additional validations were conducted by favorably comparing flow stress numerical predictions for AZ31B with literature-published histories at wide operating ranges of temperature, strain, and strain rate values. The presented methodology for finding HCP Zerilli-Armstrong material model parameters based on orthogonal cutting tests may serve as complementary alternative to time-consuming tension-compression flow stress experiments. © 2020 Elsevier B.V.