Recrystallization Process of Powder Metallurgy Tungsten Wires

Grain-shape parameters for high-temperature creep resistance in powder metallurgy tungsten fine wires

“…The figure also shows that the grains of 0.2 K/s are excessively elongated, compared with those of 985 K/s. [15] The two-dimensional aspect ratio (H/W) of grains heated at 0.2 K/s is one order of magnitude larger than those heated at 985 K/s. The final annealing temperatures of 2330 to 2760 K had little effect upon H, W, and, thereby, H/W and S/V (refer to H/W and S/V in Figure 8), although the heating rates of 0.2 to 985 K/s had a great effect on them.…”

“…The value of W was 45 to 60 m, almost independent of heating rate at the annealing temperatures of 2330 to 2760 K. [15] Substitution of W, (ϭ0.135 mm), and R in Figure 8 into Eq. The value of W was 45 to 60 m, almost independent of heating rate at the annealing temperatures of 2330 to 2760 K. [15] Substitution of W, (ϭ0.135 mm), and R in Figure 8 into Eq.…”

“…The final annealing temperatures of 2330 to 2760 K had little effect upon H, W, and, thereby, H/W and S/V (refer to H/W and S/V in Figure 8), although the heating rates of 0.2 to 985 K/s had a great effect on them. [15] Many nuclei will form and grow for a short period in the process of rapid heating, resulting in the less-elongated and interlocking grain structure, an example of which is shown in Figure 2 for a heating rate of 985 K/s. The ratio H/W, thus, appears to decrease with increasing heating rate (refer to H/W in Figure 8).…”