1. The addition of dispersed ZrO2 to a sintered 80% Ni-20% Cr alloy reduces its resistance to rupture, mainly by facilitating crack initiation. 2. The crack propagation process, being much more energy-intensive than the crack initiation process, constitutes the critical stage of the rupture of a sintered Ni-Cr alloy containing dispersed zirconia. 3. The presence of fairly evenly distributed ZrO2 particles (up to 4%) does not significantly lower the resistance to crack growth of a sintered Ni-Cr alloy. 4. The tensile mechanical properties of a sintered Ni-Cr alloy (ultimate strength σv and elongation δ) are not uniquely related to its resistance to fracture crack propagation and do not constitute a criterion by which its low-temperature service performance can be judged.