【摘要】 用仪器化冲击实验研究了尼龙6在23、-10、-50℃时的缺口冲击断裂行为。结果显示:温度对尼龙6塑性变形能力的影响导致其裂纹萌生功随温度的降低而减小。冲击曲线的惯性峰值和最大力值受材料硬度和拉伸强度的影响。在23℃时,缺口根部外表层的塑性变形导致最大应力由外表层向内部移动,所以裂纹源在次表层形成。在-10℃和-50℃时,尼龙6的塑性变形能力降低,导致裂纹源在缺口根部的外表层形成。断面形貌显示裂纹源区束状带的断裂可能是尼龙6缺口冲击时裂纹萌生的重要方式。随着温度的降低,束状带的数量减少,尺寸变大。更多还原

【Abstract】 The impact fracture behavior of nylon6 was studied by instrumented impact test under 23,-10,-50 ℃.The results showed that the crack initiation work of nylon6 reduced with temperature decreasing because of the effect of temperature on plastic deformation.The inertial peak value and the maximum force value were influenced by stiffness and tensile strength of nylon6.The crack origin formed in sub-layer under 23 ℃ because the stress in outer layer was released by its plastic deformation and the biggest axial stress moved to sub-layer.Under-10 ℃ and-50 ℃,the location of crack origins were in outer layer for the poor plastic deformation of matrix.The break of bunch belt in crack origin might be the important way of crack initiation in notched impact tests.The quantity of bunch belt became small and its size became big with temperature decreasing.更多还原