Determination of Vickers indentation fracture toughness of boronised alloyed ductile iron

Abstract

ABSTRACTIn the present study, copper (Cu), nickel (Ni), and molybdenum (Mo)-alloyed ductile iron was pack boronised at 800–850°C for 3–6 h and subsequently the microhardness and the microstructures of boride layers under different process parameters were investigated in detail. Further, Vickers indentation fracture toughness tests were executed on borided surfaces under 200 g load. The fracture toughness of borided layers was estimated separately by a series of equations and the half-length of corner cracks and the half diagonals of Vickers indents were used as variables. Generally, the values of the obtained fracture toughness were found to be higher than those of previous studies. It was found that thinner boride layers were formed at lower boronising temperatures. The highest toughness value and the thickest boride layer were obtained in the sample boronised at 850°C for 6 h.