材料期刊网

对Fe-Mn-C系2种TWIP钢Fe22Mn0.6C和Fe22Mn0.6C0.19V的显微组织、力学性能及加工硬化行为进行了研究. 结果表明, 经900℃固溶处理后的Fe22Mn0.6C0.19V钢和经800℃固溶处理的Fe22Mn0.6C钢具有晶粒尺寸相近的奥氏体组织; Fe22Mn0.6C0.19V钢在真应变ε>0.14后进入加工硬化速率平台区, 而Fe22Mn0.6C钢则在ε>0.12后即进入加工硬化速率平台区;  Fe22Mn0.6C0.19V钢在ε>0.21以后结束了加工硬化速率平台区, 其平台区明显较Fe22Mn0.6C钢短;  Fe22Mn0.6C0.19V钢加工硬化速率平台在ε>0.21以后结束是由VC沉淀粒子与TWIP钢形变孪晶相互作用引起的, VC沉淀粒子对于TWIP钢形变孪晶的产生及增殖都有明显的抑制作用.

The twinning induced plasticity (TWIP) steel has received more and more attention for its outstanding combination of good strength and high ductile. It has been proposed that deformation twinning plays an important role in controlling the deformation behavior. The formation of deformation twins is influenced by deformation temperature, strain rate, pre-deformation, grain size and precipitates. The generation of deformation twins in austenitic steel is closely related to precipitates. However, the relationship between strain hardening rate and precipitates in TWIP steels has not been clarified. In this work, the effect of vanadium carbides on the microstructure, strain hardening behavior and mechanical properties of Fe-Mn-C TWIP steel was investigated. The specimens of Fe22Mn0.6C and Fe22Mn0.6C0.19V TWIP steels with similar grain sizes were fabricated through solution treatments at different temperatures. Mechanical properties were measured by tensile tests, and microstructure evolution was observed by EBSD and TEM. The strain hardening rate (dσ/dε)-true strain (ε) curves of two steels were drawn. The results show that for the Fe22Mn0.6C0.19V steel, the strain hardening rate platform appear when true strain ε>0.14, while the strain hardening rate platform appear when the ε>0.12 for the Fe22Mn0.6C steel. The platform of Fe22Mn0.6C steel is significantly longer than that of Fe22Mn0.6C0.19V steel, The platform of Fe22Mn0.6C0.19V steel disappear quickly as true strain ε>0.21. Tensile specimens of Fe22Mn0.6C and Fe22Mn0.6C0.19V steels were observed by TEM, the results show that both the generation and propagation of deformation twins are inhibited significantly by vanadium carbides.