球墨铸铁材料细观损伤破坏机制实验研究

选用具有典型细观结构特征的球墨铸铁材料进行试验，探讨这种金属材料在各种三轴应力状态下的细观损伤破坏，结果表明：在较高三轴应力状态时，石墨颗粒与基体分离形成的一级孔洞扩展很不充分，且断裂孔洞体积分数ff较小；在较低三轴应力状态下，一级孔洞扩展较充分，损伤演化后期有二级孔洞形成，体积分数ff较大，ff的较大差异意味着材料在不同受力情况下，细观层面上表现出损伤聚合机制不同，因此用单参数f来描述和判断球铁材料损伤演化的各个物理状态是不够的。

Testing Study on Meso-damage Evolution and Failure Mechanism in Nodular Cast Iron

Nodular cast iron specimens with typical meso structure are tested to study the meso damage evolution and failure mechanism at different triaxial stress states. The results show that the large scale voids nucleated in graphite particles grow insufficiently and final failure void volume fraction f f is smaller at a higher level of triaxial stress states. But in a lower level of stress, the large scale voids grow sufficiently and the volume fraction f f is larger. It means that the meso damage evolution and coalescence mechanism is different at different triaxial stress states. So the single parameter f is not sufficient to describe and estimate the various stages of damage evolution.