Atomic probe tomography and creep deformation studies of highly dynamic metallic systems: copper-zirconium based metallic glass alloys and tin-based alloy

Abstract

The early crystallization process of a Cu-Zr binary metallic glass was investigated by transmission electron microscopy (TEM) and atomic probe tomography (APT). The microstructural analysis was carried out using different characterization methods to see if the phase separation in different chemical compositions and chemical short-range orders were investigated by applying heat treatment under argon atmosphere in differential scanning calorimetry (DSC) chamber. Such a difference in the atomic arrangement of a given amorphous metallic structure is important, the actual characterization of such small difference is not practically easy. For the reason that there is an effect of the sample preparation method which could lead to a misinterpreted of the observation since it could cause artifacts. The selection of a appropriate sample preparation method is important in direct observation of the artifact-free amorphous microstructure, since Cu-Zr binary metallic glass is promptly oxidized and hydrogenated. By prepared the sample using focus ion beam scanning electron microscope (FIB-SEM) and ion milling, oxide and hydride contamination on the sample could observe. Even the low-energy ion milling with liquid nitrogen cooling without careful measured parameters of TEM and APT could also create oxide and hydride of the alloys.

Creep deformation of Sn-1 wt% Bi was studied and compared by conventional tensile creep and nanoindentation creep. The mechanisms corresponding to creep behavior were demonstrated from the two techniques. The creep equation was able to explain the lapping process parameters. The objective of this study is to understand highly dynamic metallic system such as low melting point alloy and metallic glass alloy. This could be further applied and explained in wide range of applications.