On 2018-08-08 14:48:54
What is the hardness of aluminum alloy after heat treatment
Different models, different hardness.
Aluminum alloy has low density, high strength and good plasticity. It can be processed into various profiles. It has excellent conductivity, thermal conductivity and corrosion resistance. It is widely used in industry, and its usage is only inferior to that of steel. Some aluminum alloys can be heat treated to obtain good mechanical properties, physical properties and corrosion resistance.
Age hardening of aluminum alloy is a very complex process, which not only depends on the composition and aging process of the alloy, but also depends on the defects caused in the production process, especially the number and distribution of vacancies and dislocations. At present, it is generally believed that age hardening is the result of the formation of hardening zone by solute atom segregation.
When the aluminum alloy is quenched and heated, vacancies are formed in the alloy. During quenching, these vacancies are "fixed" in the crystal because of the fast cooling. Most of these vacancies in supersaturated solid solution are combined with solute atoms. Because the supersaturated solid solution is in an unstable state, it must change to the equilibrium state. The existence of vacancy accelerates the diffusion speed of solute atoms, thus accelerating the solute atom segregation.
The size and quantity of hardening zone depend on quenching temperature and cooling rate. One of the basic characteristics of precipitation hardening alloy system is the change of equilibrium solid solubility with temperature, that is, the increase of solid solubility with temperature. Most of the aluminum alloys that can be heat treated and strengthened meet this condition.