Project Details
Projekt
Development of an alloying element-specific flow curve model for aluminium alloys
Subject Area
Metallurgical, Thermal and Thermomechanical Treatment of Materials
Term
from 2012 to 2016
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 230561678
Process chain simulations of aluminium alloys are well developed. But since the important process of precipitation hardening, especially during quenching, could not be considered so far, there is a serious gap in the simulations.The mechanical properties of aluminium alloys are influenced by the microstructural state of the solid solution. The available alloying elements are either solved or partly embodied in precipitates of secondary phases. Measurements of the precipitation kinetics during quenching have been enabled only recently. Moreover, changes of the micro-chemical composition have been considered in simulations only with insufficient accuracy.The aim of the project is to establish an element-specific, physical material model for the mechanical characteristics of aluminium alloys under real quenching and annealing conditions. This material model is supposed to simulate flow curves in dependency of temperature and cooling rate for various alloy compositions. Perspectively, such simulations of flow curves can be integrated into FEM-simulations, with which distortions and residual stresses during quenching of aluminium components are simulated.In Aachen, the model 3IVM(+) has been in development and in use for a long time, which can simulate flow curves. However, it considers the micro-chemical influences on plastic flow insufficiently and is not suitable for small strains as in quenching distortions. For the remodelling, physical approaches exist, but they need to be realised and examined in detail. For this, the cooperation of the IMM (Aachen) and the LWT (Rostock) offers ideal conditions: With the unique equipment and the expertise at the LWT, the solution and precipitation states can be specifically selected and investigated in order to support and validate the modelling at the IMM.One subgoal is to understand the dependency of the precipitation kinetics on the type and concentration of the alloying elements, as well as their interactions. Furthermore, the connection between the solution state and the mechanical behaviour are to be worked out in a way that opens up an advanced applicability of the model. For this, investigations of highly pure laboratory alloys of the binary systems Al-Mg and Al-Si, as well as ternary Al-Mg-Si variations, are scheduled.Ultimately in this project, element specific parameters are generated which, in a broader sense, have the character of natural constants for the interaction between aluminium and its alloy elements. Such constants represent a particularly sustainable value, and with good success of the modeling, the path for other solution elements is traced.
DFG Programme
Research Grants
