热处理对Al-5.8Zn-2.7Mg-1.6Cu铝合金应力腐蚀性能的影响
发布时间：2018-09-17 18:02
【摘要】：本文研究热处理工艺对Al-5.8Zn-2.7Mg-1.6Cu铝合金的应力腐蚀性能的影响。采用光学显微镜、电子扫描显微镜研究铝合金的显微组织与相组成,通过拉伸实验测试铝合金的力学性能,运用慢应变速率拉伸试验来研究铝合金的抗应力腐蚀性能,同时还测试了铝合金的硬度、电导率。通过分析实验结果,得出了可以使Al-5.8Zn-2.7Mg-1.6Cu铝合金获得力学性能与抗应力腐蚀性能较佳的热处理工艺。主要结论如下:(1)探究了高温预析出对Al-5.8Zn-2.7Mg-1.6Cu铝合金抗应力腐蚀性能的影响规律。高温预析出可以改变晶内和晶界析出相的大小及其分布状态,能够抑制阳极溶解和抑制氢脆,从而提高合金的力学性能和抗应力腐蚀性能。经420°C预析出温度处理后,合金的应力腐蚀敏感性最低,抗应力腐蚀性能增强,但其强度和硬度会有所降低。Al-5.8Zn-2.7Mg-1.6Cu铝合金获得较佳抗应力腐蚀性能的高温预析出工艺为470℃×1h+420℃×0.5h。(2)探究了双级固溶对Al-5.8Zn-2.7Mg-1.6Cu铝合金抗应力腐蚀性能的影响规律。双级固溶中一级固溶时间和二级固溶时间是影响Al-5.8Zn-2.7Mg-1.6Cu铝合金性能的最主要因素。双级固溶的目的一是为了在一级固溶阶段发生回复,消耗变形储能,降低再结晶驱动力;二是为了让结晶相按照一定顺序溶入基体中,提高固溶温度,充分溶解第二相。通过正交试验结果得出:Al-5.8Zn-2.7Mg-1.6Cu铝合金获得较佳的抗拉强度的双级固溶工艺为440℃×90min+470℃×50min;获得较佳抗应力腐蚀性能的双级固溶工艺为450℃×120min+470℃×40min。(3)回归再时效中的预时效时间和回归温度是影响Al-5.8Zn-2.7Mg-1.6Cu铝合金性能的最主要因素。通过正交试验结果得出:Al-5.8Zn-2.7Mg-1.6Cu铝合金获得较佳的抗应力腐蚀性能的回归再时效工艺是 120℃×24h+185℃×1h+120℃×18h。(4)Al-5.8Zn-2.7Mg-1.6Cu铝合金抗应力腐蚀性能较佳的热处理工艺参数为:双级固溶(450℃×120min+470℃×40min)和回归再时效(120℃×24h+185℃×1h+120℃×18h)。(5)在低温的腐蚀环境中,Al-5.8Zn-2.7Mg-1.6Cu铝合金的抗拉强度虽然提高,但其延伸率降低,应力腐蚀敏感性也提高,抗应力腐蚀性能下降。
[Abstract]:In this paper, the effect of heat treatment on the stress corrosion resistance of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy is studied. The microstructure and phase composition of aluminum alloy were studied by optical microscope and scanning electron microscope. The mechanical properties of aluminum alloy were tested by tensile test, and the stress corrosion resistance of aluminum alloy was studied by slow strain rate tensile test. The hardness and conductivity of aluminum alloy were also tested. By analyzing the experimental results, the heat treatment process which can make Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy obtain better mechanical properties and stress corrosion resistance is obtained. The main conclusions are as follows: (1) the effect of high temperature preprecipitation on the stress corrosion resistance of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy was investigated. The pre-precipitation at high temperature can change the size and distribution of precipitated phase in crystal and grain boundary, inhibit anodic dissolution and hydrogen embrittlement, and improve the mechanical properties and stress corrosion resistance of the alloy. After 420 掳C pre-precipitation temperature treatment, the stress corrosion sensitivity of the alloy is the lowest, and the resistance to stress corrosion is enhanced. However, the strength and hardness of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy can be reduced. The high temperature pre-precipitation process for obtaining better stress-corrosion resistance is 470 鈩，
本文编号：2246693
[Abstract]:In this paper, the effect of heat treatment on the stress corrosion resistance of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy is studied. The microstructure and phase composition of aluminum alloy were studied by optical microscope and scanning electron microscope. The mechanical properties of aluminum alloy were tested by tensile test, and the stress corrosion resistance of aluminum alloy was studied by slow strain rate tensile test. The hardness and conductivity of aluminum alloy were also tested. By analyzing the experimental results, the heat treatment process which can make Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy obtain better mechanical properties and stress corrosion resistance is obtained. The main conclusions are as follows: (1) the effect of high temperature preprecipitation on the stress corrosion resistance of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy was investigated. The pre-precipitation at high temperature can change the size and distribution of precipitated phase in crystal and grain boundary, inhibit anodic dissolution and hydrogen embrittlement, and improve the mechanical properties and stress corrosion resistance of the alloy. After 420 掳C pre-precipitation temperature treatment, the stress corrosion sensitivity of the alloy is the lowest, and the resistance to stress corrosion is enhanced. However, the strength and hardness of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy can be reduced. The high temperature pre-precipitation process for obtaining better stress-corrosion resistance is 470 鈩，
本文编号：2246693
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