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通过分级淬火方法测定了2219铝合金的时间-温度-性能(TTP)曲线。结果表明:合金TTP曲线的鼻尖温度为440℃,淬火敏感温度区间为300~480℃;等温保温时,过饱和固溶体分解析出相粒子,在440℃附近,析出相(主要为θ平衡相)的析出速率达到最高;随着时间的延长,晶内θ平衡相数量增加、尺寸变大,经时效后晶内析出相θ’不均匀分布,导致强化效果显著降低,晶内出现无沉淀析出区;鼻尖温度的高相变驱动力和较快的扩散速率是θ相析出和长大的主要原因,建议在淬火敏感区间应加快淬火冷却速率避免平衡相的析出,而高于淬火敏感区间温度时可适当降低冷却速率减小热应力的影响。
The time-temperature-property (TTP) curve of 2219 aluminum alloy was determined by the graded quenching method. The results show that the tip temperature of the TTP curve is 440 ℃ and the quenching temperature range is 300-480 ℃. When isothermally retained, the phase particles are decomposed and precipitated by the supersaturated solid solution. At around 440 ℃, the precipitated phase (mainly θ equilibrium phase) With the extension of time, the amount of intratacular equilibrium phase increases and the size becomes larger. After aging, the precipitated phase θ ’is unevenly distributed, resulting in a significant decrease in the strengthening effect and the precipitation-free zone in the crystal The driving force of high phase transformation temperature and fast diffusion rate are the main causes of θ phase precipitation and growth. It is suggested that the quenching cooling rate should be accelerated to avoid the precipitation of equilibrium phase in the sensitive region of quenching, but higher than the quenching sensitive interval temperature The cooling rate can be properly reduced to reduce the impact of thermal stress.