ZG1Cr18Ni12Mo3Ti (Wangshuiganyou Immersion Etching) Microstructure
Microstructure analysis is essential for accurate evaluation of material properties and understanding of the structure-property relationship. Corrosion-assisted etching is one of the primary techniques employed in microstructure analysis as it allows for specific materials to be highlighted and easily observed. ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) is a material with low carbon, low sulfur and low phosphorus content, making it ideal for applications requiring high strength and corrosion resistance, such as laboratory and medical equipment, submarine tanks and pressure vessels. The purpose of this paper is to analyze the microstructures of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) using corrosion-assisted etching.
This corrosion-assisted etching technique was performed on samples of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) after 1-, 3-, 5- and 7-hour etching times. After etching, the specimen was dried and then analyzed using a scanning electron microscope (SEM) and optical microscope. Cross-sections were prepared by making thin slices in order to observe different features and regions of the sample.
As expected, the microstructure of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) changed significantly due to the etching procedure. After 1 hour of etching, the grains were more rounded in shape than after 7 hours of etching, which had smaller and sharper grains due to longer etching time. The grain sizes decreased with increasing etching time and showed a regular distribution of small, medium and large grains.
The surface of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) samples etched with Wangshuiganyou etchant was observed using SEM. Under high magnification, the surface revealed rod-shaped carbides and nitrides of titanium, as well as secondary carbides and nitrides of chromium, nickel and molybdenum. The surface was further examined using the secondary electron imaging and energy-dispersive spectroscopy (EDS). The elemental composition was found to be in accordance with the expected composition of the material.
Corrosion-assisted etching revealed the presence of two different grain boundaries: intergranular boundaries of zinc and chromium, and intragranular boundaries of iron, chromium and molybdenum. Etching also revealed the presence of intermetallic compounds between the grains, the majority of these being M3C and M3N(CR, NM). A small amount of M2C was also observed.
Finally, advanced methods such as focused ion beam (FIB) revealed nanoscale structures of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou). The FIB results showed a higher concentration of Ti and Mo along the grain boundaries compared to the grain interior. This suggests that the presence of Mo and Ti may play a role in the corrosion resistance of the material.
In conclusion, microstructure analysis of ZG1Cr18Ni12Mo3Ti (Wangshuiganyou) using corrosion-assisted etching revealed the presence of nanoscale intermetallic compounds in addition to the expected grain and boundary structures. The presence of Mo and Ti along the grain boundaries may indicate their role in the corrosion resistance of the material. Additional studies are needed to further investigate the corrosion resistance of this and other materials under various etching conditions.
