淬火速率對7085鋁合金時效行為的影響Effect of quenching rate on aging behavior of 7085 aluminum alloy

通過末端淬火實驗、硬度測試、透射電子顯微鏡和差示掃描量熱法，研究淬火速率對7085鋁合金時效行為的影響。結(jié)果表明：在末端淬火過程中，距離淬火端越近，淬火速率越大，時效后的峰值硬度越高。當(dāng)時效溫度較低時，淬火速率越大，則空位擴(kuò)散激活能越小，時效處理后的硬度達(dá)到峰值的時間越短，硬度值越大；隨著時效溫度的提高，不同淬火速率樣品達(dá)到峰值的時間不斷接近；當(dāng)時效溫度達(dá)到160 ℃時，不同淬火速率樣品達(dá)到峰值的時間相同，均為10 h。TEM分析結(jié)果表明：隨著淬火速率降低，淬火過程中析出的平衡相η數(shù)量和尺寸也隨之增加，時效后析出的強(qiáng)化相η'''' 數(shù)量減少，尺寸增加，彌散程度降低。

The effect of quenching rate on aging behavior of 7085 aluminum alloy was investigated by means of end quenching test, hardness test, transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). The results show that the faster the quenching rate is, the higher the peak hardness is. With the quenching rate increasing, the lower the aging temperature is, the shorter time reaching the peak hardness is and the higher the hardness gets, which is related to the decrease of the vacancy diffusion activation energy. With the aging temperature increasing, the time reaching the peak hardness gets closer and closer, when aging at 160 ℃, the peak aging time are all 10 h. TEM observation shows that, with the decrease of quenching rate, the number and the size of quench-induced equilibrium η phase increase. After aging, the number and the diffusion degree of η'''' strengthening precipitates decrease and the size becomes larger.

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