Fracture of amorphous Ni-Pd-P alloys

Mechanical behaviour, deformation and fracture have been investigated for amorphous Ni-Pd-P alloys made by an improved Pond and Maddin method. The stress-strain curves of Ni 55 Pd 35 P 10 and Ni 63 Pd 17 P 20 show quasi-brittle behaviour with average fracture stresses of 149 and 142 kg/mm 2 , respectively. These stresses are high in comparison with those of normal metals and alloys. The elongations are small, 0·042 and 0·023% for Ni 55 Pd 35 P 10 and Ni 63 Pd 17 P 20 , respectively, as is the elongation of all amorphous alloys. Fracture surfaces observed with a scanning electron microscope show two distinct regions, a featureless zone and one called a 'vein' or 'ridge' pattern. A suggested grease model gives a good simulation of the actual fracture morphology.