Fracture analysis and embrittlement phenomena of machined brass components

Fracture analysis and metallographic characterization is performed in selected machinable brass components, for use in hydraulic installations. Evidence of brittle fracture was mainly indicated by the presence of intergranular failure and limited plasticity areas. Multiple cracking was observed at the most highly stressed areas, such as the crests of the threads, the cross section transitions and thinnest wall locations. Fractographic analysis performed using Field Emission SEM, suggested the occurrence of embrittling phenomena, probably attributed to overheating and subsequent Pb-phase grain boundary segregation. Metallographic cross section investigation rather supported the failure hypothesis, implying that hot shortness is the plausible cause of ductility trough and brittle failure.