Effect of Mechanical Milling Time on Helium Irradiation Behavior of W-Nb Alloys

Mechanical milling can easily obtain nanopowders and consolidate milled powders to full density. Milling time exerts a critical influence on the performance of powders and bulk materials. In this study, the tungsten (W) combined with niobium (Nb) powder was wet milled for 15, 25, 36, and 45 h, and consolidated by spark plasma sintering. The W-Nb specimens were irradiated by 9.90 x 10(24) ions m(-2) helium (He) beams for 11 min. The results show that solid solution degree of W and Nb influences the irradiation damage of the specimen. The specimen milled for 36 h has the lowest solid solution degree, whose surface damage is the most serious among all specimens, and the nanostructure "fuzz" forms only in this specimen. In the same specimen, tungsten presents different surface damage degrees owing to its different orientations. After characterization, the W-Nb specimens were isochronally annealed at 900, 1100, and 1300 degrees C for 1 h. The grains grow in Nb-rich area but barely change in W-rich area, because Nb exerts a strong influence on the right shifting of He desorption peaks.