Mechanical behavior characteristics of metal materials at high temperature

Due to the increase of atomic diffusion ability at high temperature, the increase of the number of vacancies in the material and the change or increase of the grain boundary slip system, the high temperature strength of the material is very different from the room temperature strength. When considering the high-temperature strength of materials, in addition to the two most basic factors of temperature and mechanics, the influence of time and medium factors must also be considered. Under high temperature conditions, the deformation mechanism of the material increases, and plastic deformation is prone to occur, which is manifested by the decrease of strength, the weakening of deformation strengthening, and the increase of plastic deformation. The strength decreases with the increase of temperature, and the plasticity increases with the increase of temperature.

Under high temperature conditions, materials bear different loads, and the time required for their fracture is also different. Not only does the time to fracture decrease with increasing stress, but the form of fracture also changes. The trend of grain boundary strength and grain strength decrease with increasing temperature is different, and the intersection point corresponds to temperature T. (called isointense temperature), the material changes from transgranular fracture to intergranular fracture.

1. The strength decreases with the increase of temperature, while the plasticity increases with the increase of temperature.

2. The mechanical behavior and performance are closely related to the loading duration;

3. Even if the stress at high temperature is less than the yield strength at this temperature, the material will undergo slow and continuous plastic deformation as the load time increases, that is, the material will undergo creep.

4. At high temperature, the plasticity will decrease significantly with the increase of bearing time, the notch sensitivity of the material will increase, and the fracture will often be brittle.

5. Temperature affects the microscopic fracture mode of the material.

6. The corrosion effect of the environmental medium on the material is intensified as the temperature increases, thus affecting the mechanical properties of the material.

Therefore, the room temperature mechanical properties of the material cannot reflect its behavior under high temperature loading, and a special high temperature performance test must be carried out to determine the high temperature mechanical properties of the material;

Temperature and time are important factors affecting the high-temperature properties of Hollow Titanium Ball, so the relationship between temperature, stress and strain and time must be studied to study the high-temperature mechanical behavior of metals.