Abstract
Effect of anisotropy in compression is studied on hot rolling of AZ31 magnesium alloy with a three-dimensional constitutive model based on the quadratic Hill48 yield criterion and nonassociated flow rule (non-AFR). The constitutive model is characterized by compressive tests of AZ31 billets since plastic deformations of materials are mostly caused by compression during rolling processes. The characterized plasticity model is implemented into ABAQUS/Explicit as a user-defined material subroutine (VUMAT) based on semi-implicit backward Euler's method. The subroutine is employed to simulate square-bar rolling processes. The simulation results are compared with rolled specimens and those predicted by the von Mises and the Hill48 yield function under AFR. Moreover, strip rolling is also simulated for AZ31 with the Hill48 yield function under non-AFR. The strip rolling simulation demonstrates that the lateral spread generated by the non-AFR model is in good agreement with experimental data. These comparisons between simulation and experiments validate that the proposed Hill48 yield function under non-AFR provides satisfactory description of plastic deformation behavior in hot rolling for AZ31 alloys in case that the anisotropic parameters in the Hill48 yield function and the non-associated flow rule are calibrated by the compressive experimental results.
Highlights
Anisotropic mechanical characteristics of the AZ31 magnesium alloy have a significant influence on plastic deformation and should be considered carefully for accurate simulation of forming processes
The Hill48 yield function is combined with a non-associated flow rule (AFR) in a Hill48 form to describe the plastic behavior of AZ31 magnesium alloy
The calibrated non-AFR Hill48 yield function was implemented in a userdefined material subroutine of ABAQUS/Explicit based on a semi-implicit backward Euler method
Summary
Anisotropic mechanical characteristics of the AZ31 magnesium alloy have a significant influence on plastic deformation and should be considered carefully for accurate simulation of forming processes. [9] developed a non-AFR model based on Hill 1948 quadratic and Karafillis and Boyce nonquadratic yield functions which showed an improved prediction of the heights of deep drawn cups made of an aluminum alloy. Safaei et al [16] proposed an evolutionary anisotropic model based on non-AFR that excellently predicted distortional hardening and evolution of instantaneous R-values in seven uniaxial directions as well as balanced biaxial loading condition. Effect of anisotropy in compression on hot rolling of AZ31 magnesium alloy is studied using a non-AFR constitutive model based on the Hill 1948 yield function. The Hill yield function under non-AFR is calibrated by R-values and yield stresses from compression tests since materials mainly undergo compressive loading during hot rolling. The proposed Hill yield function under non-AFR is applied to strip rolling for the further evaluation of the proposed yield function on hot rolling processes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
