Aluminum alloy solution treatment process effect

[China Aluminum Network] aluminum alloy solution treatment process effect 1. Aluminum alloy solid solution aging heat treatment aluminum alloy casting heat treatment is to use a heat treatment specification, control the heating rate rose to a certain temperature for a certain period of time to a certain degree of insulation Speed ​​cooling, changing the structure of the alloy, its main purpose is to improve the mechanical properties of the alloy, enhance corrosion resistance, improve processing energy, and obtain dimensional stability. 2, aluminum alloy heat treatment characteristics As we all know, for the high carbon content of steel, immediately after quenching to obtain high hardness, and plasticity is very low. However, it is not true for aluminum alloys. After the aluminum alloy has just quenched, the strength and hardness do not increase immediately. As for the plasticity, it has not decreased but has increased. However, after the quenched alloy is left for a period of time (for example, after 4 to 6 days and nights), the strength and hardness are significantly increased, while the plasticity is significantly reduced. The strength and hardness of the aluminum alloy solid furnace after quenching increase significantly with time. The strength and hardness of the aluminum alloy after quenching increase significantly with time, and the strength of the aluminum alloy after quenching is called aging. Aging can occur at room temperature, called natural aging, can also be in a temperature range higher than room temperature (called aging. Aging can occur at room temperature, called natural aging, can also be in a temperature range above room temperature ( If it occurs within 100-200°C), it is called artificial aging. It occurs within (100-200°C) and is called artificial aging. 3. Age hardening of aluminum alloys The age hardening of aluminum alloys is a very complicated process. It depends not only on the composition and ageing process of the alloy, but also on the defects caused by alloy shrinkage in the production process, especially the vacancies and dislocations. Quantity and distribution, etc. It is currently believed that age hardening is the result of segregation of solute atoms to form a hardened zone. When the aluminum alloy is heated by quenching, vacancies are formed in the alloy. During quenching, these vacancies are too late to remove and are “fixed” in the crystal. These vacancies in supersaturated solid solutions are mostly associated with solute atoms. Because the supersaturated solid solution is in an unstable state, it will inevitably shift to an equilibrium state. The presence of vacancies accelerates the diffusion rate of the solute atoms, thus accelerating the segregation of solute atoms. The size and number of hardened zones depends on the quenching temperature and quenching cooling rate. The higher the quenching temperature, the greater the concentration of vacancies, the greater the number of hardened zones and the reduced size of the hardened zone. The greater the cooling rate of quenching, the more vacancies fixed in the solid solution will help increase the number of hardened zones and reduce the size of hardened zones. A basic feature of precipitation hardened alloys is their equilibrium solubility as a function of temperature, ie, increasing solid solubility with increasing temperature, most heat treatable aluminum alloys meet this requirement.