Effects of annealing temperature on the microstructure and properties of the 25Mn-3Si-3Al TWIP steel

Zhen-li Mi,Di Tang,Hai-tao Jiang,Yong-juan Dai,and Shen-sheng Li National Engineering Research Center for Advanced Rolling Technology,University of Science and Technology Beijing,Beijing 100083,China

摘 要：Microstructures and mechanical properties of the 25Mn twinning induced plasticity （TWIP） steel at different annealing temperatures were investigated. The results indicated that when the annealing temperature was 1000°C,the 25Mn steel showed ex-cellent comprehensive mechanical properties,the tensile strength was about 640 MPa,the yield strength was higher than 255 MPa,and the elongation was above 82%. The microstructure was analyzed by optical microscopy （OM）,X-ray diffraction （XRD）,and transmission electron microscopy （TEM）. Before deformation the microstructure was composed of austenitic matrix and annealing twins at room temperature; at the same time,a significant amount of annealing twins and stacking faults were observed by TEM. Mechanical twins played a dominant role in deformation and as a result the mechanical properties were found to be excellent.

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