PBT试样在不同加载速率下的断裂分析  

Effect of Loading Rate on the Tensile Fracture Properties of PBT Samples

作　　者：于杰[1,2] 都佩华[1,2] 罗筑[1,2] 何敏[1] 蒋冠森[1,2] 

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550003 [2]贵州省复合改性聚合物材料工程技术研究中心,贵州贵阳550014

出　　处：《中国塑料》2007年第4期91-95,共5页China Plastics

基　　金：贵州火炬计划项目（黔科合20008005号）

摘　　要：研究了加载速率（v）对PBT拉伸性能的影响，并对实验结果进行了分析。结果表明，随v的增大，试样断裂过程中裂纹扩展特征不同，断面形貌表现出由韧性断裂特征向脆性断裂特征的转变；断面平坦区比例参数Ap／A0随v的增加先急剧增大，当v增大到1000mm／min以上时，Ap／A0增加缓慢；断裂源处表面粗糙度参数Rs和v呈线性关系；PBT屈服强度σy随v增大先迅速增大，当v增大到1000mm／min以上时，σy基本不变；PBT的logε～σy（ε为应变速率）曲线呈明显的两段线性关系，且低速段的直线斜率小于高速段的直线斜率，并根据Eyring黏度理论对此结果进行了分析；最后采用分子链的滑动机制解释了实验现象。The effect of strain rate （v） on the tensile behavior of PBT was studied. As the loading rate grew, the fraetography transformed from ductile to brittle. The flat region ratio （Ap/A0） increased rapidly with increasing loading rate initially and leveled off at 1 000 mm/min. The study also showed that the roughness of fracture surface （Rs） increased linearly with strain rate according to R s = 2.10- 4.72 × 10^-4 v. The yield stress（σy） increased rapidly with increasing strain rate and leveled off at 1 000 mm/min. And the relationship between the yield stress and the strain rate was consistent with Eyring theory, and could be explained by the molecular chain sliding mechanics.

关 键 词：聚对苯二甲酸丁二醇酯 拉伸断裂 加载速率 断口形貌 粗糙度 

分 类 号：TQ320.774[化学工程—合成树脂塑料工业]