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向Fe-25Mn-3Si-3Al TWIP钢中添加0.35%的Nb,提高钢中C元素含量至0.1%,并配合适当热处理工艺以提高TWIP钢的屈服强度。结果表明:改进后的Fe-25Mn-3Si-3Al-0.3Nb-0.1C钢的屈服强度由原来的320 MPa提高至445 MPa,均匀伸长率则由65%降低至55%。Nb元素的添加会强烈阻碍TWIP钢的再结晶晶粒的长大,显著细化TWIP钢的奥氏体晶粒,并且添加的Nb、C元素经退火处理后主要以纳米级Nb C沉淀相的形式弥散分布于奥氏体基体上,这些细小的沉淀相将通过Orowan机制进一步提高TWIP钢的强度。此外,Nb、C元素的添加并未显著改变室温下Fe-25Mn-3Si-3Al TWIP钢的塑性变形机制,应变诱发孪晶仍然是Fe-25Mn-3Si-3Al-0.3Nb-0.1C钢的主要变形机制,奥氏体基体仍然维持着较低的层错能。通过细晶强化和沉淀强化的双重作用显著提高Fe-25Mn-3Si-3Al TWIP钢的强度,同时奥氏体基体的TWIP效应保证了改进后的TWIP钢仍具有良好的塑性。
Adding 0.35% Nb to Fe-25Mn-3Si-3Al TWIP steel, increasing the C content in the steel to 0.1%, and with the appropriate heat treatment process to improve the TWIP steel yield strength. The results show that the yield strength of the improved Fe-25Mn-3Si-3Al-0.3Nb-0.1C steel increases from 320 MPa to 445 MPa and the uniform elongation decreases from 65% to 55%. Nb addition strongly hinders the growth of recrystallized grains of TWIP steel, significantly refine austenite grains of TWIP steel, and the added Nb and C elements are mainly annealed in the nano-sized NbC precipitates Forms disperse on the austenitic matrix, and these fine precipitates will further enhance TWIP steel strength through the Orowan mechanism. In addition, the addition of Nb and C elements did not significantly change the plastic deformation mechanism of Fe-25Mn-3Si-3Al TWIP steel at room temperature, and strain-induced twins were still the main Fe-25Mn-3Si-3Al-0.3Nb-0.1C steel Deformation mechanism, the austenite matrix still maintains a low layer fault energy. The strength of Fe-25Mn-3Si-3Al TWIP steel is enhanced by the dual effect of fine grain strengthening and precipitation strengthening. The TWIP effect of austenite matrix ensures that the improved TWIP steel still has good plasticity.