10^(-2)s^(-1)压缩应变率下Al-Teflon的反应现象

Reaction of Al-Teflon under 10^(-2)s^(-1) Compression Strain Rate

采用不同的热处理工艺,得到了A类(烧结温度380℃,降温速率50℃·h^(-1))、B类(烧结温度350℃,降温速率70℃·h^(-1))两类Al-Teflon反应材料。通过准静态压缩实验对两类试件反应现象进行了测试。得到了应力应变曲线。进行了试件密度测量,SEM微观形貌分析及高速摄影观察。结果表明,B类试件发生剧烈放热反应,A类试件没有反应发生。B类试件的应变硬化模量是A类试件的5.3倍,其在应力应变平面的反应区间为:真实应变1.2~2.2,真实应力60~80 MPa。A、B两类试件结晶度分别为63%和43%。在A类试件中发现大量纳米级聚四氟乙烯纤丝,可能对材料裂纹拓展起阻碍作用。B类试件的反应现象与试件的强剪切作用及脆性开裂现象密切相关。

Two types of Al-Teflon specimens were obtained by different heat treatment processes （type A： sintering temperature 380 ℃ cooling rate 50 ℃·h^-1 , type B. sintering temperature 350 ℃, cooling rate 70 ℃·h^-1 ）. The reaction phenomenon of two kinds of specimens was tested via quasi-static compression test. The stress-strain curves were obtained. The measurement of density, micro morphology analysis of SEM and observations of high speed photography of the specimens were performed. Results show that a violent exothermic reaction is occurred for type strain hardening modulus of type 13 specimen is 5.3 times h men in the stress and strain plane is between true strain of 1 B specimen, while no reaction is occurred for type A specimen. The gher than that of type A specimen. The reaction zone of type B speci- 2 and 2.2 and true stress of 60 MPa and 80 MPa. The crystallinity of two types of specimens is 63% for type A and 43% for type B. The crystallinity of two types of Al-Teflon materials is different. A great deal of nanometer Teflon fibrils is found in type A specimen, which may hinder the crack propagation of materials. The reaction phenomenon of type B specimen is closely related to phenomenon of strong shear stress and brittle fractures of the specimen.