【摘 要】
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Aircrafts damages caused by lightning strikes have been known since the early days of aviation.However,the physical effects on the aircraft structure are still being investigated.This work seeks to evaluate the lightning strike effects in the aluminum all
【机 构】
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Department of Mechanical Engineering,Pontifícia Universidade Católica de Minas Gerais,Belo Horizonte
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Aircrafts damages caused by lightning strikes have been known since the early days of aviation.However,the physical effects on the aircraft structure are still being investigated.This work seeks to evaluate the lightning strike effects in the aluminum alloy 7075-T6.Samples were sub-mitted to lightning strike simulation in laboratory and the damages evaluated through characteri-zation techniques.Ultrasound and profilometry tests have shown material loss to 0.272 mm depth in the damaged region.In addition,it was detected the material accumulation occurrence in the damage vicinity of the region.Below the damage,it was found a region where metallurgical changes were identified.The tensile and microhardness tests results have shown reduction in the percentage elongation and hardness increasing in the material affected by lightning.These results are corrob-orated by the X-Ray Diffraction (XRD) and Rietveld Method (red line) that indicated an increasing in dislocation density and micro-deformation in the material matrix.Optical microscopy results have shown the presence of microcracks on the normal and cross-section surface of the samples damaged.The Energy Dispersive X-Ray Spectroscopy (EDXS) and Electron Backscattered Diffrac-tion Test (EBSD) found coarse intermetallic phases and precipitates compounds with dimensions greater than 1 μm in length.They were responsible for nucleation of the microcracks that propagate along the material grain boundaries.
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