Microstructure And Texture Of TWIP Steel Under The State Of Annealing And Deformation

The combination of high strength, high elongation, high strain hardening rate and high formability in TWIP steel, because of the formation of twin, which makes excellent mechanical properties of TWIP steel to improve the car’s crash safety, reduce vehicle weight. So TWIP steel has a very broad application prospect. By studying the changes in twinning and surrounding matrix, analyzing the impact of TWIP effect on performance of the material, and analyzing the evolution of texture TWIP steel under annealing, tensile and other state, which can provide a reference for lightweight and passive safety design of the car.The main contents of this paper consists of two parts.The first part is TWIP steel annealed at different temperature(1000℃, 1100℃), and using analysis and testing technology measurement XRD, EBSD to analyze at different annealing temperature recrystallization grain distribution, grain boundary character distribution and the evolution of recrystallization texture of TWIP steel annealing at different temperature. The second part is taking the tensile experiment of TWIP steel at strain rate range of 10-5~10-2 s-1. Observing the microstructure, comparing the changes of mechanical properties and the evolution of texture of TWIP steel tensiled at different strain rate.The following are showed in the results.(1) As the annealing temperature increased, the recrystallized grain size increased, Σ3CSL grain boundaries increased significantly, the strength of the main texture increased in a certain degree.(2) The content of Mn and Al elements have a huge impact on the recrystallization grain size, the impact on the formation of twin is relate with SFE. And the impact on the rcrystallization texture is complex, the type of texture is complex after annealing.(3) With the increasing of strain, the number of deformation twins increased, and deformation twins will form faster, annealing twin exist after deformation at high strain rate.(4) Under large strain rate, the strength of texture increased with increasing degree of deformation. For texture types, in addition to individual twins texture, other types of texture remained unchanged.(5) The formation of deformation twins have a large impact on the deformation texture of TWIP steel. The different compositon of TWIP corresponding to different SFE, ease of generating deformation twins are not the same, the texture types after deformation vary greatly.