中高应变率条件下TC18钛合金动态力学行为的实验研究

发布时间：2019-06-04 18:23

【摘要】：应变和应变率是影响材料力学行为的两个重要因素,分离式霍普金森压杆(SHPB)技术是实现不同应变和应变率加载的有效途径之一。为研究室温下TC18钛合金的塑性变形和破坏行为,采用SHPB,通过调节子弹长度和速度实现对TC18钛合金圆柱试样不同应变和应变率的加载。实验得到了TC18钛合金在不同应变率下的真应力-真应变曲线和同一应变率不同应变下的真应力-真应变曲线,并分别分析了应变硬化和应变率强化效应对TC18钛合金的动态力学性能的影响。实验结果表明:TC18钛合金压缩试样破坏时断口与加载方向(轴线)之间的夹角约为45°,其压缩破坏形式为典型的剪切破坏,与应变和应变率相关;应变率越高,TC18钛合金的流动应力和屈服强度越高,故该材料具有明显的应变率强化效应;绝热剪切带是裂纹形成和试样发生宏观剪切破坏的先兆。
[Abstract]:Strain and strain rate are two important factors affecting the mechanical behavior of materials. Separated Hopkinson compression bar (SHPB) technique is one of the effective ways to realize different strain and strain rate loading. In order to study the plastic deformation and failure behavior of TC18 titanium alloy at room temperature, SHPB, was used to load the cylindrical specimens of TC18 titanium alloy with different strain and strain rates by adjusting the bullet length and speed. The true stress-true strain curves of TC18 titanium alloy at different strain rates and the true stress-true strain curves of the same strain rate and different strain rates were obtained. The effects of strain hardening and strain rate strengthening on the dynamic mechanical properties of TC18 titanium alloy were analyzed. The experimental results show that the angle between the fracture surface and the loading direction (axis) of TC18 titanium alloy is about 45 掳, and the compression failure form is a typical shear failure, which is related to strain and strain rate. The higher the strain rate is, the higher the flow stress and yield strength of TC18 titanium alloy are, so the material has obvious strain rate strengthening effect, and the adiabatic shear band is the precursor to crack formation and macroscopic shear failure.
【作者单位】：北京理工大学爆炸科学与技术国家重点实验室;北京航空材料研究院;
【基金】：国家自然科学基金项目(11472054) 北京理工大学爆炸科学与技术国家重点实验室开放课题项目(KFJJ16-02M)
【分类号】：TG146.23

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