The high temperature mechanical properties of dual phase heavy metal of 95W-3.5Ni-1.5Fe alloy were investigated in tension. The specimens were prepared by liquid phase sintering. Yield strength decreased and ductility increased as the testing temperature was increased to 300°C, reached a plateau at between 300 and 500°C and then decreased considerably. The fracture modes of alloys when deformed at room temperature were a mixture of intergranular fracture and transgranular cleavage. As the temperature was increased, the percentage of intergranular cleavage increased, although transgranular fracture also remained. At higher temperatures, substantial reduction in ductility and in yield strength was a result of loss of bonding strength between tungsten grains and matrix phase.