The microstructure of extruded ingots of Ni3Al containing boron

Abstract

An investigation of the microstructure of extruded ingots of Ni₃Al containing boron (0.05, 0.09, 0.19, 0.37, 0.75, and 1.12 at.%) has been performed. The material had a nonuniform grain size and was heavily flawed (cracks, porosity). Porosity is attributed to localized melting as observed from the presence of a nodular structure within pores, while cracks are most likely due to the lack of plastic flow during the extrusion. In some alloys, after the second extrusion, a bimodal grain size was observed, which was probably caused by differing amounts of plastic strain during the extrusion.