摘要
采用机械合金化 ,随后在 6 2 0℃ ,5 8MPa下热压制备了致密的块体亚稳态纳米晶Ag5 0Ni5 0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 2 0 0h后Ag在Ni中固溶度为 4.96 %± 0 .2 1%(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。6 0 0~ 70 0℃时Ag在Ni中固溶度为 (0 .2 1~ 0 .2 4) %± 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~ 6 0nm ,退火后又长大至 10 0~ 110nm。
A bulk nanocrystalline Ag50Ni50 alloy has been prepared by hot pressing of mechanically alloyed powder at 620?℃ under a pressure of 58?MPa. 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 200?h, 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 Ni rich phases in the alloy were still in a state with certain degree of supersaturation, such as a solid solubility of Ag in Ni being 0.45%±0.11%(mole fraction). 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 mechanically alloyed powders was about 6?nm. After hot pressing, it grew to 40~60 nm and then after annealing treatment it grew further to 100~110?nm. 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.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2001年第5期741-749,共9页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目 ( 5 972 5 10 1
5 98710 5 0 )