马氏体沉淀硬化不锈钢FV520B动态力学性能及本构模型的研究

DYNAMIC MECHANICAL BEHAVIOR AND CONSTITUTIVE MODEL OF FV520B MARTENSITIC PRECIPITATION-HARDENING STEEL

为了研究马氏体沉淀硬化不锈钢FV520B的动态力学行为,采用Instron液压试验机和分离式霍普金森压杆试验装置,在不同温度(分别为20℃、100℃、300℃、500℃、700℃)和不同应变率(分别为0.001 s^(-1)、1 000 s^(-1)、3 000 s^(-1)、6 000 s^(-1))条件下对圆柱形试样进行了准静态和动态加载试验。基于Jonson-Cook和Power-Law两种本构模型对试验数据进行了拟合。试验结果表明,材料的屈服强度与流动应力随着温度升高而降低;在温度一定时,随着应变和应变率的增大,材料的流动应力增高,具有典型的温度软化、应变强化和应变率强化特性。研究表明,相比经典JonsonCook模型,Power-Law模型与试验结果吻合的更好,更适用于FV520B材料。

In order to obtain the dynamic mechanical properties of FV520 B martensitic precipitation-hardening steel,quasistatic and dynamic compression test of cylinder samples with different temperatures（ 20 ℃,100 ℃,300 ℃,500 ℃,700 ℃respectively） and strain rates（ 0. 001 s^（-1）,1000 s^（-1）,3000 s^（-1）,6000 s^（-1） respectively） were performed by Instron hydraulic testing machine and Split Hopkinson Pressure Bar（ SHPB）. Based on the Jonson-Cook and Power-Law constitutive model,the constitutive relation of material was fitted by the experiment results. The experiment results show that the yield stress and flow stress of material increase with the decrease of temperature. As the strain and strain rates increased,the yield stress increase at a certain temperature. The strain hardening effect,strain rate hardening effect and temperature effect were analyzed in this paper.It also can obtain that Power-Law model is more suited for FV520 B than Jonson-Cook model. The Power-Law constitutive model agrees well with the experimental results.