Tungsten (W) is one of the most promising plasma-facing materials in nuclear fusion devices and candidate target materials for spallation neutron source, however its applications are greatly hindered by its room-temperature brittleness and irradiation-induced embrittlement. W heavy alloys with room temperature ductility and low cost were considered as alternative materials. In this work, 93W-4.9Ni-2.1Fe alloys strengthened by nanoscale ZrC particles were fabricated by spark-plasma-sintering (SPS) and hot rotary swaging, respectively. The addition of a small amount of ZrC nanoparticles can refine grain size and increase the hardness of the WNiFe alloys, but hinder the formation of the γ-(Ni, Fe) phase during SPS. The SPS WNiFe and WNiFe-ZrC alloys are brittle at room temperature, while the swaged WNiFe and WNiFe-0.5 wt% ZrC alloys are ductile at room temperature. At 400 °C, the swaged WNiFe-0.5 wt% ZrC alloy exhibits both higher tensile strength and better ductility than the swaged WNiFe. The nanoscale particles distributed in the W grains and γ-(Ni,Fe) phase provided a good pinning effect and enhanced the strength. The thermal conductivity of swaged WNiFe-0.5 wt%ZrC is 71 Wm-1K-1 at room temperature, but it increases to about 100 Wm-1K-1 at 800 °C, which is close to that of pure W (121 Wm-1K-1). These results show the potential of WNiFe alloys as candidate materials for fusion applications.