盐雾腐蚀环境对38CrMoAl钢动态力学性能的影响

对不同周期盐雾腐蚀后38Cr Mo Al钢开展了应变速率为0.001～3000 s-1的准静态和冲击拉伸试验,研究了盐雾腐蚀环境对38Cr Mo Al钢材料在高应变率条件下动态力学性能的影响,借助数字显微镜、FT-IR、SEM、EDS等手段对盐雾腐蚀后的38Cr Mo Al钢表面形貌、腐蚀坑深度、腐蚀产物成分和断口形貌等进行了分析。结果表明,腐蚀速率与盐雾腐蚀时间正相关,腐蚀加速过程遵循幂函数特征,腐蚀产物层对38CrMoAl钢的腐蚀起到促进作用;38Cr Mo Al钢的屈服强度随着应变率的提高而提高,随着腐蚀周期的增加而降低,盐雾腐蚀后的38CrMoAl钢断口呈现多处撕裂状特征,腐蚀时间越长,撕裂状痕迹越多,撕裂状断裂使得试件断口颈缩不再是均匀发展,导致屈服后抗拉强度下降,屈强比升高。对J-C本构模型中的应变率强化项和绝热软化项进行了修正,并加入了腐蚀修正参数,使得新模型可以准确地表征38CrMoAl钢在盐雾腐蚀环境中动态力学行为。

Effect of Salt Spray Corrosion Environment on Dynamic Mechanical Properties of 38CrMoAl Steel

38CrMoAl steels were subjected to quasi-static and impact tensile tests with strain rates from 0.001 to 3000 s-1 after salt spray corrosion at different periods to investigate the effect of salt spray corrosion environment on the dynamic mechanical properties of 38CrMoAl steel materials under high strain rate conditions . The surface morphology, corrosion pit depth, corrosion product composition and fracture morphology of 38CrMoAl steel after salt spray corrosion were analyzed by means of digital microscope, FT-IR, SEM and EDS. The results show that the corrosion rate is positively correlated with the salt spray corrosion time, the corrosion acceleration process follows the power function characteristic, and the corrosion product layer promotes the corrosion of 38CrMoAl steel. The yield strength of 38CrMoAl steel increases with the increase of strain rate and decreases with the increase of corrosion cycle. The fracture of 38CrMoAl steel after salt spray corrosion shows many tear-like features. The longer the corrosion time, the more tear-like marks. The tear-shaped fracture makes the fracture necking of the specimen no longer develop uniformly, resulting in a decrease in the tensile strength and yield ratio after yielding. The strain rate strengthening term and adiabatic softening term in the J-C constitutive model were corrected, and corrosion correction parameters were added, so that the new model can accurately characterize the dynamic mechanical behavior of 38CrMoAl steel in a salt spray corrosion environment.