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采用电铸法制备了纳米晶Ni-W合金,并进行了250～500℃×1h的真空退火处理。采用激光共聚焦扫描显微镜、扫描电子显微镜、X射线衍射仪和显微硬度计等对Ni-W合金退火前后的微观组织和显微硬度进行了研究。结果表明:随退火温度的升高,纳米晶Ni-18%W合金的组织趋于均匀化;晶粒尺寸逐渐增大,从退火前的6.80 nm长大到500℃退火时的12.56 nm;在300、400和500℃退火后,有少量Ni4W相析出;在低温退火时,合金的显微硬度随退火温度的升高而升高,300℃时达到最大值,然后随退火温度的继续升高而降低。
The nanocrystalline Ni-W alloy was prepared by electroforming and annealed in vacuum at 250-500 ℃ for 1h. The microstructure and microhardness of Ni-W alloy before and after annealing were studied by laser confocal scanning microscope, scanning electron microscopy, X-ray diffraction and microhardness tester. The results show that the microstructure of nanocrystalline Ni-18% W alloy tends to be homogenized with the increase of annealing temperature. The grain size increases gradually from 6.80 nm before annealing to 12.56 nm at 500 ℃. After annealing at 300, 400 and 500 ℃, a small amount of Ni4W phase precipitated. At low temperature annealing, the microhardness of the alloy increased with the increase of annealing temperature and reached the maximum at 300 ℃, and then increased with the annealing temperature Lower.