【摘要】 利用分离式霍普金森杆对通过热压烧结法制备得到的细晶富铝Al/Fe复合材料进行了动态力学性能测试,得到了应变率为100~2300 s-1范围内材料的应力-应变曲线,并与准静态条件下(0.01 s-1)的力学性能作了对比。结果表明:随着应变率增加,材料强度提高,塑性下降,应变率为2300 s-1时的屈服强度与弹性模量分别为准静态时的7.8和2.3倍。对材料断口形貌进行了分析,断裂方式由脆性解理断裂、沿晶断裂和韧窝断裂共同组成。根据试验所得数据,构建了改进型一维弹脆性损伤本构模型,得到了试样断裂失效前的动态本构方程及式中参数的率相关特性。改进后的本构模型与实验数据吻合良好。更多还原

【Abstract】 Split Hopkinson bar was used to study the dynamic mechanical properties of fine-grained aluminium-rich Al/Fe composite materials obtained by hot-pressing sintering, and the true stress-strain curves were acquired under different strain rates(100~2300 s-1),which were compared with the properties under quasi-static situation(0.01 s-1). The results reveal that the strength of materials improves and the plasticity decreases with the increase of strain rate. The yield strength and elastic modulus under strain rate of 2300 s-1 is 7.8 and2.3 times, respectively, higher than that under the quasi-static situation. The fracture morphology has been analyzed. It is indicated that the fracture mode consists of cleavage fracture, intergranular fracture and dimple fracture. According to experimental data, a modified dimensional elastic and brittle constitutive model with damage was built, which obtained the constitutive equation before the fracture failure of specimens and the relationship between parameters and strain rate. The modified constitutive model is presented to fit the experimental data very well.更多还原