Analysis of grain boundary and micro-texture evolution during uniaxial tensile deformation of DP600 steel

Grain boundary and micro-texture evolution during the uniaxial tensile deformation of a DP600 steel were investigated. A DP600 steel was subjected to a uniaxial tensile test. The fractured specimen was sectioned, and two points with equivalent plastic strain of 0.15 and 0.4 were analyzed by electron backscatter diffraction. Results showed that the fraction of low angle grain boundaries (LAGBs) increased with increasing the plastic strain to 0.15, but a further increase in the plastic strain to 0.4 resulted in a decrease in the fraction of LAGBs. Furthermore, increasing the plastic strain led to the generation of geometrically necessary dislocations around the ferrite-martensite and ferrite-ferrite boundaries, as represented by the increase in the kernel average misorientation with increasing plastic strain. Analysis of grain average misorientation and grain orientation spread revealed that both parameters have higher values within the smaller ferrite grains and those surrounded by many martensite islands. The main texture components in the DP600 steel were along the α and γ fibers, which were replaced by strong cube and moderate rotated cube components with increasing the plastic strain. Subsequently, the Schmid factor for the {110}<111> slip system increased as a result of the formation of the cube texture. Based on the above results, it was concluded that the finer ferrite grains surrounded by many martensite islands are more susceptible to damage formation during tensile deformation.