(1. 中国科学院 金属研究所, 沈阳 110016;
2. 中国科学院 金属腐蚀与防护国家重点实验室， 沈阳 110016)
摘 要: 采用机械合金化，随后在620 ℃，58 MPa下热压制备了致密的块体亚稳态纳米晶Ag50Ni50合金，用X射线衍射仪、扫描电镜和透射电镜研究了其组织结构。晶格常数的精确测定结果表明，球磨200h后Ag在Ni中固溶度为4.96%±0.21%(摩尔分数)，Ni在Ag中固溶度为0.84%±0.30%(摩尔分数)，热压以后仍具有过饱和固溶度，Ag在Ni中为0.45%±0.11%(摩尔分数)，在相近温度下稳定化处理后进一步脱溶。600～700℃时Ag在Ni中固溶度为(0.21～0.24)%±0.11%(摩尔分数)，Ni在Ag中固溶度小于0.1%(摩尔分数)。机械合金化粉末的晶粒度约为6nm， 热压后长大至40～60nm，退火后又长大至100～110nm。探讨了晶粒度与内应力同时作用下X射线衍射峰的展宽问题和纳米晶结构对快速致密化的作用。
关键字: 块体纳米晶合金； 过饱和； 快速致密化； Ag50Ni50
Ag50Ni50 alloy prepared by hot pressing
of mechanically alloyed powders
（1.Institute of Metal Research， Chinese Academy of Science，
Shenyang 110016,P.R.China;
2. State Key Laboratory for Corrosion and Protection,
Chinese Academy of Science, Shenyang 110016, P.R.China）
Abstract:A bulk nanocrystalline Ag50Ni50 alloy has been prepared by hot pressing of mechanically alloyed powder at 620℃ under a pressure of 58MPa. The microstructural characteristics of the alloy were studied by X-ray diffraction (XRD)， scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that after mechanical alloying for 200h， a solid solubility of Ag in Ni reached 4.96%±0.21%(mole fraction) and Ni in Ag reached 0.84%±0.30%(mole fraction). After hot pressing， the Ag-and Nirich phases in the alloy were still in a state with certain degreeof supersaturation， such as a solid solubility of Ag in Ni being 0.45%±0.11%(molefraction). The results also reveal that the solubility of Ag in Ni is (0.21～0.24)%±0.11%(mole fraction) and that of Ni in Ag is less than 0.1%(mole fraction) at 600～700℃. The grain size of the mehanically alloyed powders was about 6nm. After hot pressing, it grew to 40～60 nm and then after annealing treatment it grew further to 100～110nm. Furthermore， the influence of the variation of the grain size and the internal stress on the broadening of the X-ray diffraction peaks was evaluated in detail and the role of the nanocrystalline structure in the fast densification process of the powders was also discussed.
Key words: nano-crystallined bulk alloy； super-saturation； fast densification； Ag50Ni50
