Abstract
The effect of the heat treating time is investigated to improve the mechanical properties of W-Ni-Fe heavy alloys. These alloys were annealed in the temperature at 400-1200°C in vacuo for annealing time range 1-24 h after cold-worked by swaging treatment. It is confirmed that the values of tensile strength, yield strength and hardness are increased, but the elongation is decreased by heat treatment in vacuo after swaging in the temperature at 600°C for 5 h. However, the tensile strength, yield strength and hardness are decreased, and also the elongation is increased in the temperature at 1200°C for 3 h.
The scanning electron micrographs of the fracture surfaces show that heat treatment strengthens mainly the interface between tungsten-matrix phase boundaries and W-W grain boundaries.
