The factors that influence aluminum alloy
include aging temperature, the time from quenching to artificial aging, the chemical composition and the solution treatment of the alloy.
Effect of aging temperature
At different temperatures, the critical nuclei of the precipitated phase are different in size, number, composition and agglomeration. When the temperature is too low, the G·P region is not easy to form because it is difficult to spread, the strength and hardness are low after aging; when the temperature is too high, the diffusion is easy and the critical nuclei of the precipitated phase in the supersaturated solid solution are big, and the strength and hardness are low after aging. Therefore, the various alloys have their most suitable aging temperatures.
1. Effect of the time from quenching to artificial aging
It was found that some aluminum alloys such as Al-Mg-Si alloys remained at room temperature and then subjected to artificial aging. The strength index of the alloy can not reach the maximum value, while the plasticity increased. Like ZL101 aluminum alloy casting
which was kept at room temperature after quenching for a day and then subjected to artificial aging, its maximum strength is 10~20Mpa lower than that of artificial aging right after quenching, but its plasticity is better.
2. The influence of the chemical composition of the alloy
Can alloy be strengthened by aging? Firstly it depends on if the alloy elements can be dissolved in the solid solution and the degree of solid solubility with temperature changes. For example, solid solubility of silicon and manganese in aluminum is relatively small, and with little change when the temperature changes. Though magnesium and zinc has a bigger solid solubility in aluminum, its structure that was form with aluminum is almost the same as the substrate, and the strengthen effect is minimal. Therefore, we don't adopt strengthen aging treatment for binary aluminum-silicon, aluminum-manganese, aluminum-magnesium, aluminum-zinc. And for some binary alloys, such as aluminum-copper alloys, and ternary alloys or multicomponent alloys like aluminum-magnesium-silicon, aluminum-copper-magnesium-silicon alloys, which have solubility and solid transformation during heat treatment and can be enhanced by heat treatment.
3. The effects of alloy solution treatment
In order to obtain good aging effect, higher quenching heating temperature and longer holding time are conducive to obtain the maximum saturation of the uniform solid solution under the conditions of not overheating, oversintering and grain growth. In addition, we should not precipitate the second phase in the quenching process, or the precipitated phase will play crystal nucleus role and causes partially uneven precipitation and reduce the aging effect.