Research status of titanium and titanium alloy surface self-nano technology

Research status of titanium and titanium alloy surface self-nano technology

1 Surface self-nano technology based on surface mechanical grinding

The surface mechanical grinding method is the earliest method used to nanorize the surface of materials.The projectile in the airtight container is driven by a vibrator to vibrate at high speed, and the projectile hits the top sample at different angles. With the accumulation of the number of impacts, the plastic deformation on the surface of the material causes the grain to gradually refine.

2 Surface self-nano technology based on surface mechanical milling

The surface mechanical milling method is a new type of metal surface self-nano technology developed by Liu et al.The cylindrical sample rotates at a speed of v1 relative to the hemispherical WC/Co tool, and the tool moves axially along the processed sample at a speed of v2. The tip of the tool is in contact with the surface of the sample under the action of a preset pressure, and the friction force on the contact surface produces a plastic deformation area.

3 Surface self-nano technology based on high-energy shot peening

Shot Peening technology is very common in industrial production, mainly by launching a large number of high-speed projectiles to hit the surface of the material, causing it to produce plastic deformation and changing the internal stress of the surface to improve the surface properties of the material.

4 Surface self-nano technology based on ultrasonic impact

Ultrasonic impact technology (also known as ultrasonic shot peening) uses ultrasonic waves to be transmitted to the impact terminal through an intermediate mechanism (projectile, impact head or firing pin can be used as the impact terminal). The huge impact load will cause the surface grains of the metal material to break, resulting in high-density dislocations, thereby realizing the nanization of the material surface.

5 Surface self-nano technology based on supersonic particle bombardment

The supersonic particle bombardment method uses the principle of gas-solid dual-phase flow. The supersonic air flow drives a large number of hard particles to bombard the surface of the material. The great kinetic energy coupled with repeated bombardment causes the surface of the material to undergo severe plastic deformation and continuously refine the grain to the order of nanometers.

6 Surface self-nano technology based on laser impact

Laser impact technology (also known as laser shot peening technology) uses high-power laser pulses to illuminate the surface of the material. The plasma explosion generated by the heating and vaporization of the absorbent layer on the surface of the material will produce a high-pressure shock wave on the surface of the material, acting on the surface of the material and generating residual stress in it.

7 Outlook

1. The surface nano-layer obtained by surface self-nanization is relatively thin, with a thickness of less than a few hundred microns, which is not significant enough to improve the overall performance of the material. The comprehensive influence of deep surface nano-structural layers on the properties of titanium alloys can be studied in the future.

2. Other surface strengthening technologies such as surface coating and surface deposition can be integrated with self-nano-chemical processes to develop hybrid nano-chemical technologies to improve processing efficiency and optimize material properties.

3. At this stage, there are relatively few simulation studies on the self-nanization of titanium alloy surfaces, so it can be integrated with mechanics, materials science and other disciplines to establish the correspondence between relevant process parameters and nanostructure gradients through simulation models to guide the development of engineering practice.

4. Titanium alloy is widely used in aviation engines. It is very important to study its fatigue, wear and corrosion behavior under complex working conditions such as high temperature, high pressure, vibration, etc., and more in-depth surface nano-research is required.