几种典型材料的动态硬度研究

Dynamic Indentation Hardness of Typical Materials

通过在金刚石维氏压头上施加单次压缩脉冲,压头动态压入材料获得动态压痕,建立动态硬度测试系统;测试了2A12铝合金、45钢、AZ31镁合金、AD95氧化铝陶瓷等典型材料的动、静态硬度。结果表明:所测试材料的动态硬度均高于静态硬度,在高应变率加载条件下,材料具有更高的压入变形抗力。金属材料动态硬度较静态硬度提高的幅度与材料的晶体结构类型有关,反映了被测材料的应变率硬化能力;而陶瓷压痕区材料受到周向材料惯性约束作用,裂纹形核和生长被抑制,动态硬度较静态硬度大幅提高。动态硬度可以有效表征材料的动态力学性能。

A dynamic indentation hardness measuring system was established successfully by loading a single compressive pulse on the diamond Vickers indenter and examining the dynamic indentation size and dynamic load value.The dynamic hardness of several typical materials such as 2A12 aluminum alloy,45steel,AZ31 magnesium alloy and AD95 alumina was tested with such dynamic hardness testing system.The results show that the dynamic hardness is higher than static hardness of all the materials used in the current investigation,i.e.,the materials have a higher deformation resistance during dynamic indentation.For metallic materials,the increment of hardness under dynamic conditions is strongly dependent on the crystal structure,and can reflect the ability of strain rate strengthening of materials.For the ceramic,AD95 alumina,the greater increase of dynamic hardness can be attributed to the inertial confinement around the indentation,which consequently inhibits the nucleation and growth of cracks.The dynamic hardness can efficiently characterize the dynamic mechanical properties of materials.