【摘要】 采用光学显微镜、扫描电子显微镜、X射线衍射仪、透射电子显微镜及拉伸试验机等,研究了3种成分的中锰轻质钢在不同变形量(0～30%)时的组织演化和力学性能,并分析了其拉伸行为和变形机制。结果表明:3种试验钢的显微组织均由铁素体和奥氏体两相组成,力学性能良好,其强塑积均超过了30 000 MPa·%。在拉伸变形过程中,锰含量较低的Fe-3. 67Mn-4. 99Al-0. 28C钢中奥氏体含量随着变形量的增加而降低,发生了奥氏体向α’马氏体的渐进式转变,即产生了TRIP效应;锰含量较高的钢在变形过程中发生了TWIP效应,使其具有较好的塑性。Fe-10. 46Mn-5. 14Al-0. 24C钢中还发生了奥氏体向ε马氏体的转变,该转变显著发生在变形量10%～30%之间; Fe-11. 38Mn-5. 36Al-0. 87Cr-0. 52C钢中未发生相变,变形过程中观察到的高密度位错墙可能是其强度较高的原因之一。更多还原

【Abstract】 Optical microscope,scanning electron microscope,X-ray diffractometer,transmission electron microscope and tensile tester were used to study the microstructure evolution and mechanical properties of three kinds of medium-Mn lightweight steels with different deformations( 0 to30%),and the tensile behavior and deformation mechanism were analyzed. The results showed that all the three tested steels exhibited microstructures composed of ferrite and austenite,excellent mechanical properties,and product of strength and elongation of more than 30 000 MPa·% .During the tensile deformation,the volume fraction of austenite in Fe-3. 67 Mn-4. 99 Al-0. 28 C steel with lower manganese content decreased with the deformation increasing,and austenite was gradually transformed into α’-martensite,i. e.,TRIP effect occurred; TWIP effect occurred in the steels with higher manganese content during deformation, thus having better plasticity. Meanwhile, the transformation of austenite to ε-martensite was also observed in Fe-10. 46 Mn-5. 14 Al-0. 24 C steel,the transformation occurred between 10% and 30% deformations. No phase transformation occurred in Fe-11. 38 Mn-5. 36 Al-0. 87 Cr-0. 52 C steel,and the high-density dislocation wall observed during deformation might be one of the reason for its high strength.更多还原