Rielli Vitor Vieira, Theska Felix, Primig Sophie
School of Materials Science & Engineering, UNSW, Sydney, NSW2052, Australia.
Microsc Microanal. 2021 Apr 20:1-11. doi: 10.1017/S1431927621000349.
Plasma focused ion beam microscopy (PFIB) is a recent nanofabrication technique that is suitable for site-specific atom probe sample preparation. Higher milling rates and fewer artifacts make it superior to Ga+ FIBs for the preparation of samples where large volumes of material must be removed, for example, when trying to avoid lift-out techniques. Transmission Kikuchi diffraction (TKD) is a method that has facilitated phase identification and crystallographic measurements in such electron transparent samples. We propose a procedure for preparing atom probe tomography (APT) tips from mechanically prepared ribbons by using PFIB. This is highly suitable for the preparation of atom probe tips of interfaces such as interphase boundaries from challenging materials where lift-out tips easily fracture. Our method, in combination with TKD, allows the positioning of regions of interest such as interfaces close to the apex of the tip. We showcase the efficacy of the proposed method in a case study on Alloy 718, where the interface between γ-matrix and δ-phase has not been yet extensively explored through APT due to preparation challenges. Results show depletion of γ″-precipitates near the γ/δ interface. A quantitative evaluation of the composition of phases in the bulk versus near the interface is achieved.
等离子体聚焦离子束显微镜术（PFIB）是一种适用于特定位置原子探针样品制备的新型纳米加工技术。更高的铣削速率和更少的伪像使其在制备必须去除大量材料的样品时优于Ga +聚焦离子束，例如，在试图避免剥离技术时。透射菊池衍射（TKD）是一种有助于在此类电子透明样品中进行相鉴定和晶体学测量的方法。我们提出了一种通过使用PFIB从机械制备的薄带制备原子探针断层扫描（APT）尖端的程序。这非常适合于制备来自具有挑战性的材料（如界面边界）的原子探针尖端，因为剥离尖端很容易断裂。我们的方法与TKD相结合，可以将感兴趣的区域（如靠近尖端顶点的界面）定位。我们在718合金的案例研究中展示了所提出方法的有效性，由于制备挑战，γ基体和δ相之间的界面尚未通过APT进行广泛研究。结果表明γ/δ界面附近的γ″析出物减少。实现了对块状相与界面附近相组成的定量评估。
