Effect of microstructure evolution during plastic deformation on the formability of Transformation Induced Plasticity and Quenched & Partitioned AHSS

摘要

The effect of strain path on the microstructure evolution of two different advanced high strength steel alloys (AHSS alloys) has been studied in this work. The two AHSS alloys considered are Transformation induced Plasticity (TRIP) and Quenched and Partitioned (Q&P) steels. The formability of these AHSS was calculated at different strain paths using limit dome height (LDH) tests. Both of these AHSS show unusual formability behavior at the stretching region of the Forming Limit Diagram (FLD). A comprehensive microstructure and texture study was performed at different strain levels and near the principal strain paths to understand the effect of microstructure on the formability of these AHSS. This study clearly highlights the significance of development of a and gamma fibre texture, at different strain paths, affecting the formability of AHSS steels. Additionally, the evolution of other microstructure and crystallographic texture features such as phase transformation, misorientation development, texture intensity and Taylor's factor also affect the formability of these AHSS. It has also been observed that gamma fibre, maximum orientation distribution (ODF), texture intensity and misorientations are reduced in the stretching region and decrease the formability of these AHSS. (C) 2018 Elsevier Ltd. All rights reserved.