(中南大学 材料科学与工程学院， 长沙 410083)
摘 要: 利用TTP曲线的测定和透射电镜分析对铝车车体大型材用6005A合金的淬火敏感性进行了研究。 结果表明， 6005A合金的HB与σb的TTP曲线鼻温均在370℃左右， 高温区淬火敏感性并不太高， 但中温区（280～400℃）淬火敏感性极高， 低温区则介于二者之间； 大型材生产中在线挤压后淬火时，型材出口温度最好应大于480℃， 自480℃空冷到分解危险温度400℃时间最好小于60s, 此后要快速淬火通过中温危险区。 透射电镜分析表明：随着等温时间的延长， 6005A合金过饱和固溶体不断分解为平衡析出相Mg2Si， 强化效果减弱，同时抑制了强化相β＇的析出， 合金的力学性能也随之降低。
关键字: 6005A合金； TTP（time—temperature—properties）曲线; 淬火敏感性
aluminum alloy
（School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract:The quench sensitivity of 6005A alloy was studied using TTP (time—temperature—properties) diagrams plotted by HB and σb values and transmission electron microscopy (TEM). The results show that the nose temperatures of TTP curves are about 370℃. The quench sensitivity at low temperature is quite lower than that at moderate temperature, but is much higher than that at high temperature. It is concluded that, in the industrial production of section material, the outlet temperature after on-line extruding should be higher than 480℃, air-cooling time from 480℃ to critical temperature (400℃) should be shorter than 60s and the quench rate should be quick enough through moderate temperature. It is ascribed to the fact that supersaturated solid solution decomposes into equilibrium phase Mg2Si continuously with increasing isothermal time so that the strengthening effect decreases. It suppresses the formation of major strengthening phase β＇ and is detrimental to mechanical properties of 6005A alloy.
Key words: 6005A aluminum alloy; TTP diagrams; quench sensi
