Grain Size-Dependent Mechanical Properties of a High-Manganese Austenitic Steel
来源期刊：Acta Metallurgica Sinica2019年第6期
论文作者：Xiao-Jiang Wang Xin-Jun Sun Cheng Song Huan Chen Shuai Tong Wei Han Feng Pan
文章页码：746 - 754
摘 要：The effect of grain size on the mechanical properties of a high-manganese（Mn） austenitic steel was investigated via electron-backscattered diffraction, transmission electron microscope, X-ray diffraction, and tensile and impact tests at 25 °C and-196 °C. The Hall–Petch strengthening coefficients for the yield strength of the high-Mn austenitic steels were 7.08 MPa mm 0.5 at 25 °C, which increased to 14 MPa mm 0.5 at -196 °C. The effect that the grain boundary strengthening had on improving the yield strength at-196 °C was better than that at 25 °C. The impact absorbed energies and the tensile elongations were enhanced with the increased grain size at 25 °C, while they remained nearly unchanged at -196 °C. The unchanged impact absorbed energies and the tensile elongations were primarily attributed to the emergence of the micro-twin at -196 °C, which promoted the cleavage fracture in the steels with large-sized grains. Refining the grain size could improve the strength of the high-Mn austenitic steels without impairing their ductility and toughness at low temperature.
Xiao-Jiang Wang1,2，Xin-Jun Sun2，Cheng Song1，Huan Chen2，Shuai Tong2，Wei Han2，Feng Pan1
1. School of Materials Science and Engineering, Tsinghua University2. Department of Structural Steels, Central Iron and Steel Research Institute
摘 要：The effect of grain size on the mechanical properties of a high-manganese（Mn） austenitic steel was investigated via electron-backscattered diffraction, transmission electron microscope, X-ray diffraction, and tensile and impact tests at 25 °C and-196 °C. The Hall–Petch strengthening coefficients for the yield strength of the high-Mn austenitic steels were 7.08 MPa mm 0.5 at 25 °C, which increased to 14 MPa mm 0.5 at -196 °C. The effect that the grain boundary strengthening had on improving the yield strength at-196 °C was better than that at 25 °C. The impact absorbed energies and the tensile elongations were enhanced with the increased grain size at 25 °C, while they remained nearly unchanged at -196 °C. The unchanged impact absorbed energies and the tensile elongations were primarily attributed to the emergence of the micro-twin at -196 °C, which promoted the cleavage fracture in the steels with large-sized grains. Refining the grain size could improve the strength of the high-Mn austenitic steels without impairing their ductility and toughness at low temperature.
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