PSI - Issue 5

George Pantazopoulos et al. / Procedia Structural Integrity 5 (2017) 476–483 G. Pantazopoulos and A. Vazdirvanidis/ Structural Integrity Procedia 00 (2017) 000 – 000

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Fig. 3: (a-b) SEM fractographic analysis (BSE imaging) showing brittle intergranular fracture (IGF) region with pronounced grain boundary decohesion and shallow cusps on the grain facets, (c-d) mixed mode of brittle intergranular fracture and shallow dimpled fracture showing evidence of limited plastic deformation. Note the presence of massive accumulation of Pb covering a significant fraction of the fracture surface. (e-f) Cross section SEM (BSE imaging) showing several aspects of the unfolding sequence of “liquid metal embrittlement” mechanism depicting mo lten metal flow and “flooding” on crack faces while prominent interganular cracks are nucleated at areas replenished with Pb. The microstructure seems typical for leaded brass consisting of bright α -phase grains surrounded by Pb dispersoids in a “dark” β -phase matrix. Hardness was measured approximately to 135 HV 0.2 .