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A Mechanism of Hot‐spots Formation at the Crack Tip of Al‐PTFE under Quasi‐static Compression
Author(s) -
Feng Bin,
Li Yuchun,
Hao Hong,
Wang Huaixi,
Hao Yifei,
Fang Xiang
Publication year - 2017
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.201700106
Subject(s) - materials science , composite material , brittleness , fracture (geology) , compression (physics) , crack closure , brittle fracture , microstructure , inert , fracture mechanics , composite number , chemistry , organic chemistry
Generally, the Al‐PTFE (polytetrafluoroethylene) is thought to be inert under quasi‐static or static loads. However, it was found that Al‐PTFE would initiate under quasi‐static compression after a specific heat treatment procedure and the opening fracture plays a crucial role in the initiation. A unique micrographic fracture pattern which showed unstable crack propagation and a ductile‐to‐brittle transition was observed at openning cracks by SEM. Combining the observed microstructure with the stress distribution at the path of crack propagation derived from numerical simulation, a mechanism was proposed to explain the formation of “hot‐spots” at the crack tip. The temperature rise at the crack tip was estimated to be at least 612 °C, which is high enough to ignite the Al‐PTFE composite.