机械球磨时间对W-Nb合金氦辐照行为的影响

Effect of mechanical milling time on the helium irradiation behavior of W-Nb alloys

摘要:

实验采用不同球磨时间制备W-Nb复合粉末,并通过放电等离子烧结方法制备W-Nb复合材料。所得的W-Nb复合材料用剂量为9.90×10₂₄ ions/m₂的氦离子束辐照11分钟,随后分别在900、1100和1300℃下热处理1小时。实验结果表明,球磨时间不同导致复合材料中钨铌固溶程度不同,进而造成了材料抗辐照损伤性能的差异。其中,球磨36小时的试样的固溶程度最低,其在辐照后表面损伤也最严重,表面出现了纳米绒毛状结构。此外,在同一个样品中,钨的不同的晶面取向也导致了不同的表面损伤形貌。通过对比不同热处理温度的试样,发现富铌区域的晶粒发生了明显的长大,但富钨区域的表面形貌几乎没有变化。这是由于铌的加入使得He在钨中的解吸峰右移。

Abstract:

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 with 9.90 × 10₂₄Sions/m₂ helium (He) beams for 11 min. The solid solution degree of W and Nb influences the irradiation damage of the specimen. The surface damage of specimen milled for 36 h which has the lowest solid solution degree is the most serious among all specimens, such that the nanostructure “fuzz” is formed only in the said 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 °C for 1 h. The grains grow in Nb but barely change in W. Nb exerts a strong influence on the right shifting of He desorption peaks.