超高强度钢AF1410塑性流动特性及其本构关系

在本文中，为揭示超高强度钢AF1410的塑性流动性，并研究其塑性流动本构关系，利用CSS4410电子万能试验机和改进的Hopkinson拉压杆技术，对AF1410钢在温度从100K到600K，应变率从0.001/s到2000/s，塑性应变超过20%的塑性流动特性进行了试验研究。结果表明，拉伸加载下AF1410钢屈服强度低于压缩屈服强度，且随应变率增加，拉压屈服强度差值越来越大；该材料塑性流动应力对应变率敏感性低，而对温度较为敏感；随应变率的提高，该材料拉伸失效应变减小，但温度对失效应变无明显影响。最后基于位错的运动学关系，借助试验数据，获得了AF1410钢的塑性流动物理概念本构模型，并通过与经典J-C模型的结果对比对该物理概念本构模型进行了评估分析，表明该物理概念本构模型在较宽温度和应变率范围能较好的预测AF1410钢的塑性流动应力。

PLASTIC FLOW CHARACTERISTICS AND CONSTITUTIVE RELATION FOR ULTRA HIGH STRENGTH STEEL AF1410

In this paper, to understand the plastic flow characteristics of ultra high strength and toughness steel AF1410, and build the constitutive relations of this steel, using a CSS4410 qusia-static test machine and enhanced Hopkinson pressure and tension bar technique, uniaxial compression and tension tests are both performed. True strains exceeding 20% are achieved in these tests, over the range of strain rates from 0.001/s to about 2000/s, and at initial temperatures from 100K to 600 K. The results demonstrate that: the yield stress in tension loading is lower than it in compress loading, and the difference between the compress and tension yield stresses become larger, with increasing strain rate; the plastic flow of AF1410 steel is not very sensitive to the changes of strain rate, but is relatively sensitive to temperature; the failure strain decreases with the increasing strain rate, but is not evidently affected by temperature. Finally, based on the mechanism of dislocation motion, paralleled with a systematic experimental investigation, a physical conception constitutive model is obtained for the deformation of AF1410 steel, and is evaluated by the classical J-C model. It shows that the plastic flow of AF1410 steel, in a large range of strain rates and temperatures, could be predicted by physical conception constitutive model.