Multiscale Modeling of ZE20 Mg Extrusion Alloy
The desire to decrease weight in the automotive industry has led to the study of Magnesium (Mg) and its alloys as a viable replacement for Aluminum. Extrusions are particularly attractive for parts such as the subframe and bumper beam, which can be extruded in one step to manufacture the part. Unfortunately, Mg alloys currently do not demonstrate enough ductility at lower temperatures to be a suitable replacement economically. A lower ductility requires Mg alloys to be extruded at lower speeds or higher temperatures, requiring more time and energy to manufacture Mg parts.
The previously stated problems lead to the application of integrated computational materials engineering (ICME) to better understand Mg alloys and more accurately model extrusions. The use of constitutive models is a great way to obtain data from various length scales, as shown in Figure 1, and apply that data to a single material model of different extrusion types. Each length scale gives relevant information to be passed on to the next length scale as well as be used in the overall constitutive model. First the requirements of the structural scale application needs to be known and then a top down design mentality can be applied. Figure 2 shows the flow of information between each bridge as well as the information that will be passed up to the macroscale internal state variable (ISV) model.