Optical and Electron Microscopy Investigation of Damaged Storz Firehose Couplings Microstructure

This paper presents the results of a microscopic investigation of fractured Storz type fire hose couplings. It is part of the authors’ previous investigations on the failure mechanisms of this type of couplings. The investigations were performed using optical and scanning electron microscopy with Field Emission Gun (FED) and X-ray Energy Dispersive Spectrometer (EDS). It is shown that the AlSi5Cu1Mg casting alloy, used for the fabrication of these couplings, presents a normal microstructure. Thus, the nucleation and growth of micro-cracks in the investigated couplings are not related to the alloy’s microstructural defects and must be generated by a different process.