Formation of Self-Oriented Nanocrystals in an Amorphous Alloy under Focused-Ion-Beam Irradiation

我们在室温下用聚焦离子束（FIB）辐照在Ni-P非晶合金中形成了晶体学取向的纳米晶体（NC）。照射平面的透射电子显微镜观察显示在整个照射区域形成NC。从一系列电子衍射分析，确定所形成的NC的结构为Ni的面心立方（fcc），并且确认所形成的NC的以下取向：||<111>fcc和FIB方向||<110>联邦通讯委员会所形成的NC由具有孪生关系的两个变体组成，孪生平面是照射平面。这些孪晶相关晶体具有平均畴尺寸约为200 nm的畴状微观结构。非晶合金的弹性各向异性不影响所形成的纳米碳的晶体学特征。从晶体学和几何学的角度来讨论控制所形成的NC的取向的功能。研究了Ni-P非晶合金表面纳米晶的晶体学特征随入射FIB角的变化。当平行于非晶膜照射时，形成纳米晶体，而当垂直于非晶膜照射时，不形成纳米晶体。这表明，nancrystals，这已经形成了以前，可以擦除FIB照射从垂直于非晶薄膜。我们已经成功地使用这种技术的纳米晶体图案。纳米晶体的晶粒尺寸控制的可能性也试图通过在FIB照射之前低于结晶温度的预热处理。

We have formed oystallographically oriented nanosized crystals(NCs) in a Ni-P amorphous alloy using focused-ion-beam(FIB) irradiation at room temperature. Transmission electron microscopy observations of the irradiated plane revealed the formation of NCs throughout the irradiated area. From a series of electron diffraction analyses, the structure of the formed NCs was determined to be face-centered cubic(fcc) of Ni and the following orientation of the formed NCs was confirmed : Irradiated plane normal ||<111>fcc, and FIB direction ||<110>fcc. The formed NCs consisted of two variants which have a twin relation, the twinning plane being the irradiated plane. These twin related crystals have a domain-like microstructure with an average domain size of approximately 200 nm. The elastic anisotropy of the amorphous alloy does not affect the crystallographic features of the formed NCs. The features which control the orientation of the formed NCs are discussed from crystallographic and geometrical points of view. Changes in the crystallographic features of the NCs as a function of the incident FIB angle on the irradiated plane of Ni-P amorphous alloy have been also investigated. When irradiating parallel to the amorphous film, nanocrystals were formed, whereas nanocrustals were not formed when irradiating perpendicular to the amorphous film. This suggests that nancrystals, which had been formed previously, can be erased by FIB irradiation from perpendicular to the amorphous film. We have succeeded the patterning of nanocrystals using this technique. The possibility of grain size control of nanocrystals is also attempted by pre-heat treatments below crystallization temperature before FIB irradiation.