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利用扫描电镜、透射电镜、背散射电镜及拉伸和冲击试验研究了锰对含锰量为3%~12%的Fe-Mn合金组织和力学性能的影响。结果表明,当锰含量介于3%~9%时,随着锰含量的上升,高温相变产物(多边形铁素体和准多边形铁素体)受到抑制,合金的屈服强度和抗拉强度逐渐增加而均匀延伸率和总延伸率逐渐下降;当锰含量增加至12%时,合金中残留的少量亚稳ε马氏体和奥氏体在形变初期发生相变,产生的相变塑性使合金呈现出屈服强度下降的假象,但合金的抗拉强度、均匀延伸率和总延伸率均上升。由于晶界锰原子浓度的增加会减弱界面的结合力,故合金的冲击韧性随锰含量的增加而显著下降。为使Fe-Mn合金获得较好的综合力学性能,应控制锰含量小于7%或在基体中引入适量的亚稳相。
The effects of manganese on the microstructure and mechanical properties of Fe-Mn alloys containing 3% ~ 12% manganese were investigated by scanning electron microscopy, transmission electron microscopy, backscattered electron microscopy and tensile and impact tests. The results show that when the manganese content is between 3% and 9%, the high temperature transformation products (polygonal ferrite and quasi-polygonal ferrite) are suppressed with the increase of manganese content, and the yield strength and tensile strength of the alloy gradually increase While the elongation and elongation decreased gradually. When the content of manganese increased to 12%, a small amount of metastable ε martensite and austenite remained in the alloy during the early phase of deformation, resulting in the phase change plasticity of the alloy Showing the illusion of yield strength decline, but the alloy tensile strength, uniform elongation and total elongation are increased. Due to the increase of the concentration of manganese atoms in the grain boundary, the binding force of the interface will be weakened, so the impact toughness of the alloy decreases remarkably with the increase of Mn content. In order to obtain better mechanical properties of Fe-Mn alloy, manganese content should be controlled less than 7% or the introduction of the right amount of metastable phase in the matrix.