Mechanisches Verhalten metallischer Werkstoffe über weite Bereiche der Dehnung, der Dehnrate und der Temperatur

摘要

In this work the mechanical behaviour of the aluminium alloy AA6060 and the steel 42CrMo4 each of them in two different heat treatment conditions was analysed at quasi-static strain rates up to high dynamic loading at temperatures from RT up to 400°C for the aluminium alloy respectively 800°C for the steel. For the examination of the mechanical behaviour compression tests have been conducted on cylindrical and square-shaped specimens. Both heat treatment conditions of the aluminium alloy AA6060 show just little strain hardening influence and very small adiabatic softening up to high strain rates. But the aluminium alloy shows a quite distinctive temperature dependency that is hardly influenced by the strain rate. At lower temperatures to 200°C there is almost no strain rate dependency detectable up to a strain rate of 100s-1. Above there is partly a negative tendency recognizable before a strong increase in flow stress at high strain rates (>1000s-1). This effect is called “drop-effect”. It was already detected in former studies at similar aluminium alloys. The steel 42CrMo4 in the heat treatment condition 1 (quenching at 850°C, water cooling, quenching at 375°C for 1h) shows nearly no temperature dependency up to 200°C. The influence at higher temperatures gets compensated by the influence of the strain rate that is increasing with the temperature as well. The flow curves at a strain rate of 100s-1 are almost on the same level. In the heat treatment condition 2 (quenching at 850°C, water cooling, quenching at 600°C for 1h) the steel 42CrMo4 shows a little more distinctive temperature dependency but up to a temperature of 400°C there can nearly no influence of the strain rate be found. Above this temperature the flow stress level is continuously rising with the strain rate. Independent from the temperature there is a strong increase concerning the strain rate sensibility above 100s-1. After interpretation of the experimental results an approach for a mathematical description of the flow behaviour of both analysed materials was introduced as well as the development of a material law was explained that contained the influence of the strain, the strain rate and the temperature. Finally the used parameters were determined. For a first validation a simulation model was created afterwards. As material data the developed material law including the appraised parameters were used. The results show a very good conformity between experiments and simulation.