November 2019 Volume 1

FORGING RESEARCH

Modelling of the Forging Process for a Magnesium Alloy Automotive Control Arm by Talal Paracha A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Master of Applied Science in Mechanical and Mechatronics Engineering Waterloo, Ontario, Canada, 2018 © Talal Paracha 2018 Author’s Declaration I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. Abstract The automotive industry has placed significant emphasis on weight reduction to achieve better fuel economy while maintaining safety and quality standards. One way this can be achieved is by using forged magnesium alloys due to their high stiffness- and strength-to-weight ratios. In order to assess the feasibility of forging magnesium alloys into a complex automotive component, numerical simulation using the commercial Finite Element (FE) package DEFORM 3D was performed and verified. For this study, two magnesium alloys AZ80 & ZK60 in extruded forms were considered. Key material parameters required for input into DEFORM 3D included material flow stress data as a function of temperature, strain rate and strain. This data was extracted from flow curves which were developed by others in this research group using uniaxial hot compression tests of the as-cast and extruded starting material. Since magnesium has a Hexagonal Close Packed (HCP) crystal structure with limited slip systems which are activated under different deformation conditions, it was determined that anisotropy which is induced through the processes such as rolling, extrusion and forging plays an important role during deformation. As a result, Hill’s anisotropic material model available in DEFORM 3D was used. Hill’s anisotropic material model requires a strain rate sensitive flow curve for each temperature in addition to 6 anisotropic coefficients. Anisotropic coefficients were generated using measured compression and shear yield strength in the

FIA MAGAZINE | NOVEMBER 2019 46