Al_2O_3陶瓷材料高应变率下的动态力学性能

Dynamic Mechanical Properties of Al_2O_3 Ceramics Under Higher Strain-Rate

针对常规SHPB实验系统的不足对其进行改进,采用改进的SHPB实验方法对Al2O3陶瓷材料的动态力学性能进行了实验研究,表明改进的SHPB实验方法可以成功地进行高强度材料高应变率下的动态力学性能实验。实验得到了Al2O3陶瓷材料在不同应变率下的动态应力应变曲线,结果表明,Al2O3陶瓷为弹脆性材料,其动态应力应变呈非线性关系;在高应变率下,陶瓷材料的动态应力应变关系是应变率相关的,材料的初始弹性模量、破坏应力、破坏应变值随应变率的增大而增大。最后对Al2O3陶瓷高应变率下的变形机理进行了讨论。

The general test technique of Split Hopkinson Pressure Bar（SHPB） was modified aiming at its shortcomings. The dynamic mechanical properties of Al2O3 ceramics are investigated using the modified SHPB technique. It is indicated that the modified SHPB technique is effective for the materials with high strength to carry the dynamic mechanical property test under higher strain-rate. The stress strain curves for different strain-rates were gained. It is shown that Al2O3 ceramic is nonlinear elastic-brittle material. This material is sensitive to strain-rate at higher strain--rate. The dynamic modulus of elasticity and dynamic compressive strength of ceramic increase with increase in strain rate. Finally, the deformation mechanism of Al2O3 ceramics under higher strain-rate is discussed.