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Material Sciences 2020
Zn/Mg比对7003铝合金挤压型材组织与性能的影响
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Abstract:
中高强型Al-Zn-Mg合金的腐蚀性能及力学性能的综合调控在工程应用上尤为重要。本文以不同Zn/Mg比的7003铝合金挤压型材为对象，在(Zn + Mg)总量约为6.6 wt.%的冶金质量下，通过室温拉伸、晶间腐蚀等分析测试方法，并采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)分别对微米级第二相和纳米级时效析出相进行观察，研究了Zn/Mg比对力学性能和抗晶间腐蚀性能的影响规律。结果表明：在120℃的峰值时效状态下，Zn/Mg比从11.4降至6.1，7003-T6铝合金中η’相分布密度增加，使抗拉强度和屈服强度分别提高34.1%和47.4%，而第二相体积分数的减少及PFZ的窄化使得延伸率仅降低了1.1%。加之晶界析出相从连续转变为断续分布的状态，降低了7003铝合金的晶间腐蚀倾向性。
The comprehensive regulation of the corrosion and mechanical properties of medium-high strength Al-Zn-Mg alloys is particularly important in engineering applications. In this paper, 7003 aluminum alloy extruded profiles with different Zn/Mg ratios are taken as the object. At the metallurgical mass of 6.6wt.% of total (Zn + Mg), the analysis and test methods such as room temperature tensile and intergranular corrosion are adopted. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe the microscale second phase and nanoscale aging precipitated phases, respectively. The influence of Zn/Mg ratio on mechanical properties and resistance to intergranular corrosion was studied. Results show that under the peak aging condition at 120？C, the Zn/Mg ratio decreases from 11.4 to 6.1, the distribution density of η’ phase in 7003-T6 aluminum alloy increases, which increases the tensile strength and yield strength by 34.1% and 47.4%, respectively. And the reduction of the volume fraction of the second phase and the narrowing of the PFZ reduced the elongation by only 1.1%. In addition, the grain boundary precipitation phase changes from continuous to discontinuous distribution, which reduces the tendency of intergranular corrosion of 7003 aluminum alloy.
| [1] | Ludtka, G.M. and Laughlin, D.E. (1982) The Influence of Microstructure and Strength on the Fracture Mode and Toughness of 7XXX Series Aluminum Alloys. Metallurgical Transactions A, 13, 411-425. https://doi.org/10.1007/BF02643350 |
| [2] | 章淑芳, 王晓敏, 陈辉. 7003铝合金动车柜体的应力腐蚀开裂[J]. 材料工程, 2015, 43(7): 105-112. |
| [3] | 李慎兰, 黄昌龙, 黄志其. 固溶处理工艺对7003铝合金组织和性能的影响[J]. 材料热处理学报, 2015, 36(2): 42-48. |
| [4] | Sha, G. and Cerezo, A. (2004) Early-Stage Precipitation in Al-Zn-Mg-Cu Alloy (7050). Acta Materialia, 52, 4503-4516. https://doi.org/10.1016/j.actamat.2004.06.025 |
| [5] | 章国辉, 杨修波, 黄磊萍. 人工时效7055铝合金晶间腐蚀形貌与微观机理的关系[J]. 稀有金属材料与工程, 2018, 47(11): 3393-3399. |
| [6] | Dong, P., Chen, S. and Chen, K. (2019) Effects of Cu Content on Microstructure and Properties of Super-High-Strength Al-9.3Zn-2.4Mg-xCu-Zr Alloy. Journal of Alloys and Compounds, 788, 329-337. https://doi.org/10.1016/j.jallcom.2019.02.228 |
| [7] | 刘晓涛, 崔建忠. Al-Zn-Mg-Cu系超高强铝合金的研究进展[J]. 材料导报, 2005, 19(3): 47-51. |
| [8] | Deng, Y., Wan, L. and Zhang, Y. (2011) Influence of Mg Content on Quench Sensitivity of Al-Zn-Mg-Cu Aluminum Alloys. Journal of Alloys and Compounds, 509, 4636-4642. https://doi.org/10.1016/j.jallcom.2011.01.147 |
| [9] | Carroll, M.C., Gouma, P.I. and Mills, M.J. (2000) Effects of Zn Additions on the Grain Boundary Precipitation and Corrosion of Al-5083. Scripta Materialia, 42, 335-340. https://doi.org/10.1016/S1359-6462(99)00349-8 |
| [10] | 欧世声, 邓运来, 刘胜胆. 锌镁元素含量对新型Al-Mg-Zn合金组织和力学性能的影响[J]. 热加工工艺, 2017, 46(24): 135-139. |
| [11] | Maloney, S.K., Hono, K. and Polmear, I.J. (1999) The Chemistry of Precipitates in an Aged Al-2.1Zn-1.7Mg at.% Alloy. Scripta Materialia, 41, 1031-1038. https://doi.org/10.1016/S1359-6462(99)00253-5 |
| [12] | 屈华, 刘伟东, 张旭. Zn/Mg比对Al-Zn-Mg合金时效析出惯序的影响[J]. 稀有金属材料与工程, 2018, 47(6): 1766-1770. |
| [13] | Lin, Y.C., Zhang, J. and Chen, M. (2016) Evolution of Precipitates during Two-Stage Stress-Aging of an Al-Zn-Mg-Cu Alloy. Journal of Alloys and Compounds, 684, 177-187. https://doi.org/10.1016/j.jallcom.2016.05.161 |
| [14] | 侯泽北, 夏山林, 高建宇. 不同热处理工艺对7003铝合金组织和性能的影响[J]. 热加工工艺, 2016, 45(16): 249-252. |
| [15] | 张伟彬. 多元Al合金扩散系数研究及扩散行为模拟[D]: [硕士学位论文]. 长沙: 中南大学, 2012. |
| [16] | 单际强, 侯丹丹, 张今捷. 6082铝合金电化学腐蚀行为及晶间腐蚀机理研究[J]. 腐蚀科学与防护技术, 2018, 30(4): 353-361. |
| [17] | 刘贵立, 方戈亮. Al-Zn-Mg-Cu超高强铝合金晶界偏聚与腐蚀机制研究[J]. 稀有金属材料与工程, 2009, 38(9): 1598-1601. |
