热压成型工艺制备PTFE/Al活性材料及其力学性能与撞击释能特性

Mechanical Properties and Impact Energy Release Characteristics of PTFE/Al Hot Pressing Active Materials

为解决烧结工艺制备聚四氟乙烯/铝(PTFE/Al)存在成型时间长、温度过高等问题,采用冷压(25℃)与热压(180、200、220、240、300、330℃)方法制备PTFE/Al活性材料;利用准静态压缩试验,测试了活性材料的准静态力学性能;利用落锤测试系统定量分析撞击点火响应,以研究不同热压成型温度下活性材料力学性能及释能特性;采用阿基米德方式测试了活性材料的密度。结果表明,PTFE/Al活性材料在压制过程中存在密实均匀区,在40 MPa外界高压下可得到较为密实的试样;不同热压成型温度下的PTFE/Al活性材料呈脆性,抗压强度在11~13 MPa,当热压温度为300℃时,活性材料抗压强度最大为13.5 MPa,同时也具有一定的释能特性;当热压温度升高时PTFE/Al活性材料有更高的断裂韧性。由于成型温度不同,同时也导致其释能效率与初始激发能不同,与冷压成型试样相比,热压成型(300℃)试样释能效率提高3%左右。

To solve the problems of long molding time and high temperature in the preparation of polytetrafluoroethylene/aluminum(PTFE/Al)by sintering process,the PTFE/Al active materials were obtained using cold pressing(25℃)and hot pressing(180,200,220,240,300,330℃)methods.The quasi-static mechanical properties of active materials were analyzed by quasi-static compression test.To assess the mechanical properties and energy release characteristics of active materials at different hot pressing temperatures,the impact ignition responses were analyzed quantitatively by drop height test system.The density of active materials were tested by Archimedes method.The results show that the PTFE/Al active materials have a density homogenization area during the pressing process,and the relative compact sample can be obtained under 40 MPa.PTFE/Al active materials under different hot pressing temperatures are brittle with compressive strength of 11—13 MPa.When the hot pressing temperature reach to 300℃,the maximum compressive strength of active materials is 13.5 MPa,and also has a certain energy release efficiency characteristics.The PTFE/Al active materials have higher fracture toughness when the hot pressing temperature rises.Due to different pressing temperatures,the energy release efficiency and the initial excitation energy are different.Compared with the cold pressing sample,the energy release efficiency of hot pressing(300℃)sample is improved by about 3%.