|
Identification of fatigue damage Al alloy treated with SLM technology using acoustic emission method
Zemanová, Lucie ; Mazůrek, Ivan (referee) ; Mazal, Pavel (advisor)
The aim of the diploma thesis is to study fatigue properties of EN AW-2618A aluminium alloy produced by selective laser melting (SLM). S-N diagrams of reference alloy and SLM material depending on manufacturing conditions were constructed. Reference alloy had the same chemical composition as the SLM material, but it was made by traditional technology (by extruding). While testing, acoustic emission (AE) and resonant frequency of loading was monitored. Fractographic analyses of fracture surfaces were performed. It was found, that SLM material has significantly worse fatigue performance. Fatigue properties are strongly dependent on SLM process parameters settings and precise observance of procedure. The most significant differences in cyclic degradation were found in the length of the stages of fatigue. The more homogeneous the material is, the longer the nucleation stage compared to the total lifetime is. The main source of AE in case of the reference material is plastic deformation on the tip of the crack. For SLM testing, stronger acoustic activity was recorded, because brittle fracture of the material between discontinuities, which is stronger AE source, is more frequent.
|
guest ::
