Effects of Cu addition on the precipitation hardening response and intergranular corrosion of Al-5.2Mg-2.0Zn (wt.%) alloy
Effects of Cu addition on the precipitation hardening response and intergranular corrosion of Al-5.2Mg-2.0Zn (wt.%) alloy
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效果%20of%20Cu%20添加%20上%20%20析出%20硬化%20响应%20和%20晶间%20腐蚀%20of%20Al-5.2Mg-2.0Zn%20(wt.%)%20合金
DOI：
10.1016/j.matchar.2016.11.004
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发表时间：
2016-12-01
影响因子：
4.7
通讯作者：
Zhang, Jishan
中科院分区：
文献类型：
--
作者：
Cao, Cheng;Zhang, Di;Zhang, Jishan
0.45重量%的影响研究了Cu对Al-5.2Mg-2.0Zn（wt%）合金沉淀硬化和晶间腐蚀的影响。结果表明，Cu的加入一方面通过促进GP区的析出，显著改善了Al-5.2Mg-2.0Zn合金的时效硬化性能，使T-Mg-32（Al，Zn）（49）（Im 3，a = 1.422 nm）相在峰值时效状态下的弥散分布更加均匀;高峰值硬度的原因是晶粒内T相密度增加、T相细化、T相强化能力增强和无析出带宽度变窄。Cu的加入虽然对T相的析出动力学没有影响，但提高了T相的热稳定性。另一方面，Al-5.2Mg-2.0Zn-0.45Cu合金抗IGC性能的提高是由于PFZ宽度变窄，腐蚀电位增加，腐蚀电流密度降低。晶粒内沉淀物的体积分数越高，通过降低晶粒和PFZ之间的腐蚀电位差，也可能有助于提高IGC抗性。(C)2016 Elsevier Inc. All rights reserved.
Effects of 0.45 wt.% Cu addition on the precipitation hardening response and intergranular corrosion (IGC) of Al-5.2Mg-2.0Zn (wt%) alloy have been investigated in this research. Results suggest that, on one hand, Cu addition improves the age hardening response of Al-5.2Mg-2.0Zn alloy significantly by stimulating the precipitation of GP zones during pre-aging treatment, which results in finer dispersion of the T-Mg-32(Al, Zn)(49) (Im3, a = 1.422 nm) phase in peak aged condition. The higher peak hardness results from the higher density and finer T phase inside grain, increased strengthening ability of the T phase and the narrower width of precipitation free zones (PFZ). Though Cu addition has no effect on the precipitation kinetics of the T phase, it improves the thermal stability of the T phase. On the other hand, the improved IGC resistance of the Al-5.2Mg-2.0Zn-0.45Cu alloy is due to the narrower width of PFZ and increased corrosion potential combined with decreased corrosion current density. Higher volume fraction of precipitates inside grain may also contribute to the improved IGC resistance by reducing the corrosion potential difference between the grain and the PFZ. (C) 2016 Elsevier Inc. All rights reserved.