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The influence of cold rolling reduction on microstructure and mechanical properties of the twinning induced plasticity(TWIP) steel with a chemical composition of Fe-20Mn-3Si-3Al-0.045 C has been investigated.Tensile tests were carried out to explore the mechanical properties of TWIP steel with different cold rolling reductions.The microstructures were observed by optical microscopy and transmission electron microscopy(TEM).The misorientation and the development of recrystallization texture in TWIP steel sheets were investigated by Electron Back Scatter Diffraction(EBSD) technique.The results indicated that the steel exhibited attractively mechanical properties when cold rolling reduction was about 10%.The tensile strength of the steel with a rolling reduction of 10%is higher than 900 MPa and the yield strength is about 800 MPa,while the elongation is above 35%.The microstructure is composed of austenitic matrix and deformation twins at room temperature,at the same time,a significant amount of deformation twins,stacking faults and dislocations are observed by TEM.TEM observations showed the presence of deformation twinning in the sample at low rolling reduction.As the strain increases the volume fraction of twins increases.Mechanical twins play a dominant role during deformation and result in excellent mechanical properties for the investigated steel.By TEM observation,the possible deformation mechanisms can be suggested as:with the increasing strain,formation of the twin will gradually play a more important role during deformation.The interaction between twins and dislocations enhances the strain hardening rate in the sample.Consequently,the necking is delayed and a good ductility is obtained.Twins were always observed in the region with high density of dislocation and faults,suggesting that the interaction among blocked dislocations and faults as well as deformation twins promote the increase in material strength.EBSD observation showed that the textures has evolved according to the following trend:the brass orientation {110}〈112〉and Goss orientation {110}〈001〉are dominant at every strain level,those intensities increase with increasing strain,while with the increase of the strain level,the change of S orientation {123}〈634〉was not obviously.
The influence of cold rolling reduction on microstructure and mechanical properties of the twinned shot plasticity (TWIP) steel with a chemical composition of Fe-20Mn-3Si-3Al-0.045C has been investigated. Sensile tests were carried out to explore the mechanical properties of TWIP steel with different cold rolling reductions. Microstructures were observed by optical microscopy and transmission electron microscopy (TEM). The misorientation and the development of recrystallization texture in TWIP steel sheets were investigated by Electron Back Scatter Diffraction (EBSD) technique. The results indicate that the steel drawn attractively mechanical properties when cold rolling reduction was about 10%. tensile strength of the steel with a rolling reduction of 10% is higher than 900 MPa and the yield strength is about 800 MPa while the elongation is above 35% The microstructure is composed of austenitic matrix and deformation twins at room temperature, at the same time, a significant am ount of deformation twins, stacking faults and dislocations are observed by TEM. TEM observations showed the presence of deformation twinning in the sample at low rolling reduction. As the strain increases the volume fraction of twins increases. Mechanical twins play a dominant role during deformation and result in excellent mechanical properties for the bent steel. BY TEM observation, the possible deformation mechanisms can be suggested as: with the increasing strain, formation of the twin will gradually play a more important role during deformation. interaction between twins and dislocations enhances the strains hardening rate in the sample.Consequently, the necking is delayed and a good ductility is obtained. twins were always observed in the region with high density of dislocation and faults, suggesting that the interaction among blocked dislocations and faults as well as deformation twins promote the increase in material strength. EBSD observation showed that the textures has evolved according to the following trend: the brass orientation {110} <112> and Goss orientation {110} <001> are dominant at every strain level, those intensities increase with increasing strain, while with the increase of the strain level, the change of S orientation {123} <634> was not obviously.