Metallographic corrosion method of high niobium titanium alloy, the polished metallographic sample is wiped 3 ~ 5 times with corrosive liquid on the surface of the metallographic sample that needs to be corroded, and then wiped 3 ~ 5 times with oxidizing solution, so repeatedly alternating until a better effect is achieved. The invention makes use of different tissues to form oxide film with different difficulty, thus affecting the subsequent corrosion, thereby improving the display contrast of different tissues. The invention can realize metallographic corrosion of high niobium content titanium alloy in rolling state, solid solution state and aging state. The obtained sample grain boundary phase boundary is clear and complete, and the operation is simple, convenient and fast. The problems of low contrast of each structure in metallographic picture after corrosion and difficult to distinguish in high niobium titanium alloy were solved.
Titanium alloy has the characteristics of strength, high density, good ductility, good toughness and corrosion resistance, so titanium alloy is widely used in aerospace and other fields requiring high mechanical properties and lightweight and corrosion resistance. By adding a high content of niobium in titanium alloy, the solid solution treatment can make the titanium alloy maintain the body-centered cubic structure at room temperature, which further improves the shape of this titanium alloy. Because the titanium alloy with body-centered cubic structure is not stable, it can undergo phase transformation under the action of plastic deformation, so it can have superelastic and shape memory effects. The addition of niobium makes the elastic modulus of titanium alloy decrease and the corrosion resistance improve further. This low modulus titanium alloy has a certain elastic deformation ability, so it has a certain shape adaptive performance, in the fine parts with high precision requirements, using it as fasteners can not only prevent loosening, but also reduce damage. In addition, when the elastic modulus of this titanium alloy is close to human bone, bone absorption caused by stress shielding can be effectively avoided.
In order to study the properties of titanium alloy, it is necessary to display and observe the microstructure of titanium alloy to determine its fine microstructure, so as to lay the foundation for improving the properties of titanium alloy. Because of the strong corrosion resistance of high niobium titanium alloy, the corrosion time is long and the effect is not good by using Kroll reagent, a common etch agent of titanium alloy. In addition, although some patented corrosives for high niobium titanium alloys can also be corroded, but often the contrast is small, the picture always has a hazy sense, and for particularly subtle parts, it is not a good display. This problem of low contrast often cannot be ameliorated by simply changing the caustic composition.
