PEI拉伸断口典型形貌特征及其随加载速率的变化

Fractographic Characteristic of PEI Tensile Fracture and Its Change at Different Loading Rate

选用特种工程塑料PEI,对其拉伸断裂的断口形貌进行了系统地宏观和微观观察,总结了PEI拉伸断面的典型形貌特征,并研究了各典型形貌随加载速率的变化规律。宏观断口分析表明:加载速率≦1 mm/min时,可将断面划分为平坦区、粗糙区和最后断裂区;拉伸速率>1 mm/min时,可将断面划分为平坦区、肋区和最后断裂区。微观断口分析和定量测试表明:平坦区可分为3种特征类型,且随加载速率升高,平坦区面积先呈迅速下降趋势,然后趋于平缓;粗糙区的典型形貌为礼花形貌,且随裂纹的扩展,粗糙区的粗糙度呈逐渐减小的趋势;肋状形貌由光滑带和粗糙带交替组成,且随加载速率增大,断面肋条宽度增大。

The fracture morphology of tensile fracture of PEI was observed systematically, the typical morphology characteristics of tensile failure section of PEI was summarized, and the change of all kinds of typical morphology with the different loading rate was studied. Macroscopic fracture analysis showed that the fracture surface could be divided into the flat area,the rough area and the last fracture area when the loading rate was lower than 1 mm/min,and the fracture surface could be divided into the flat area,the rib area and the last fracture area when the loading rate was higher than 1 mm/min. The micro fracture analysis and quantitative test indicated that the flat area could be divided into three types of characteristics. The proportion of the flat area decreased and then flatten our as the loading rate increased. The typical morphology of the rough area was fireworks morphology. The roughness of the rough area reduced gradually with the expansion of the crack. The rib morphology consisted of smooth band and rough band. With the increased of loadin~ rate,the width of rib band increased.