科研之友
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摘要
The automotive industry is in a constant search for steels with improved mechanical properties to reduce the weight of structural components and thus, increase the efficiency of the vehicles. Unfortunately, most efforts to increase the strength result in a decrease of the ductility, which is detrimental to crash performance. However, there is a new family of advanced high strength steels which present outstanding strength and ductility properties. These steels are known as TWIP (TWinning Induced Plasticity) steels and their peculiarity is that they deform by twinning. Usually, high Mn contents, i.e. 20-25%Mn, are necessary to stabilize austenite at room temperature and control the stacking fault energy in values which promote twinning as the main deformation mechanism. In this study, the hot deformation characteristics of a TWIP steel were evaluated. This aspect is important in order to control the hot working operations and consequently, the final microstructure and mechanical properties of the steel. With this purpose, hot compression tests were performed at temperatures ranging from 800 degrees C to 1200 degrees C and strain rates from 0.1 s-1 to 0.001 s-1. Moreover, double hit compression tests were carried out at 900 degrees C with different interpass times in order to evaluate the static recrystallization kinetics at such temperature. Detailed metallographic examination was done by optical microscopy to assess the dynamic and static recrystallization characteristics of the steel in terms of recrystallized fraction and recrystallized grain size.
- 出版日期2011-8
