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纳米晶材料(nc-)首先由Gleiter和他的合作者提出,并用惰性气体淀积法(IGC)所获得.这些纳米颗粒在真空下原位加压成型.纳米晶材料的平均直径一般采用X-射线衍射法测定.引起X射线衍射峰展宽有两个因素:小的颗粒直径和晶体缺陷造成的内应力.在惰性气体淀积法(IGC)过程中,由于金属蒸气迅速冷却凝聚,可能形成过饱和固溶体而处于非平衡状态;另一方面金属合金蒸气中的溶质原子浓度的涨落会改变溶质在纳米颗粒中的浓度,这都可能使X射线衍射峰展宽.因此除用X射线衍射法外,结合其他方法是必要的.AgCu合金是研究这一效应的最佳材料.Kumpmann用示差热分析(DSC)来研究nc-AgCu合金,观察到大的放热反应,这与过饱和α-Ag和α-Cu的析出有关.
Nanocrystalline material (nc-) was first proposed by Gleiter and co-workers and was obtained by inert gas deposition (IGC) .These nanoparticles were press-formed in situ under vacuum.The average diameter of the nanocrystalline material was generally calculated using X - Determination of X-Ray Diffraction The broadening of the X-ray diffraction peak is due to two factors: small particle diameter and internal stress due to crystal defects During the inert gas deposition (IGC) process, metal vapor may form due to rapid cooling and condensation Supersaturated solid solution in the non-equilibrium state; the other hand, the metal alloy vapor solute atomic concentration fluctuations will change the concentration of solute in the nanoparticles, which may broaden the X-ray diffraction peak.Therefore, except by X-ray diffraction Combined with other methods is necessary.AgCu alloy is the best material to study this effect.Kumpmann differential thermal analysis (DSC) to study the nc-AgCu alloy, a large exothermic reaction was observed, which is supersaturated α- Ag and α-Cu precipitation related.