Highly damped alloy

Highly damped alloys are used in the manufacture of parts that require vibration and noise reduction, which can achieve the purpose of improving the working accuracy of machines, extending their life, acoustic stealth and reducing noise nuisance. Damping is the performance of the material to attenuate its own vibration, measured by the specific damping ψ, is the vibration energy consumed for one week of vibration, W is the kinetic energy at the beginning of the week, and ψ is equivalent to the measure of amplitude logarithmic reduction rate δ and internal consumption, etc.

The damping of a sample is commonly measured by the torsional pendulum method and the resonant bar method. The damping originates formally from the non-ideal elasticity of the stress-strain relationship of the material, and during vibration, the stress-strain diagram forms a hysteresis line, and the area of the line represents the vibration energy lost during a week

Generation mechanism
(1) Complex phase type, where the material consists of two phases, hard and soft, producing microplastic deformation at the interface between the two phases and within the soft phase;
(2) Ferromagnetic type. Inelastic strain is produced by the rotation of the magnetic domains or the movement of the domain walls under the stress of the ferromagnetic material;
(3) Interface type. In martensitic phase change materials, twin interfaces or phase interfaces move under stress to produce additional strain;
(4) Dislocation type. The hysteresis movement of dislocations in the material. Several mechanisms can act simultaneously in one material. Highly damped alloys include iron-based, manganese-copper-based, magnesium-based, nickel-titanium-based, copper-based, aluminum-zinc-based alloys, and highly damped cast iron.

Highly damped alloys are used in the manufacture of parts that require vibration and noise reduction, which can achieve the purpose of improving the working accuracy of machines, prolonging the life, acoustic stealth and reducing noise public hazards. In the aerospace, ship, vehicle and machine manufacturing industries. The damping performance of high damping alloys is related to the working conditions, such as stress state, stress amplitude, frequency, temperature and magnetic field, etc. Some materials have the phenomenon of damping performance degradation, which should be noted when using