Multi-scale modelling of pre-strain dependent precipitation strengthening in 6xxx series alloys in a deformed componentWednesday (08.11.2017) 12:40 - 13:00 Part of:
6xxx series alloys are widely used as both body panels and structural components in the automotive industry in order to reduce the weight of cars and their energy consumption. The final strength of the alloys is mainly determined by the formation of the precipitates. Precipitation kinetics is sensitive to the straining and thermal treatment in the processes, i.e. solution heat treatment (SHT), natural ageing (NA), pre-ageing (PA), forming and final paint bake treatment (PB). This causes a new set of challenges in finite element modelling for failure and damage simulation, since the local mechanical properties vary as a consequence of the inhomogeneous spatial distribution of the precipitates which is itself caused by the local strain differences.
In this work, a microstructure model which considers both temperature and strain influences on nucleation and growth of precipitates during PB was applied. The model representing the microstructure evolution was then coupled to a yield strength model, which takes the main strengthening mechanisms originating from solutes and precipitates into account. A material property model was developed and applied to map the results of the final PB component from a deformed component by applying the microstructure and yield strength models. The approach is validated by the comparison with microstructure data, yield strength and a cross-die test.