文章信息/Info

Title:

Effect of Grain Size on Stress Corrosion Cracking Behavior of LY12 Alloy

作者:

孫忠志; 王瑞陽; 于美; 李松梅; 王宗武; 劉建華

(1.沈陽飛機設計研究所，遼寧 沈陽 110035）��
（2.北京航空航天大學材料科學與工程學院，北京 100191)

Author(s):

SUN Zhongzhi;  WANG Ruiyang;  YU Mei;  LI Songmei;  WANG Zongwu;  LIU Jianhua

(1.Shenyang Aircraft Design & Research Institute, Shenyang 110035, China)��
(2.School of Materials Science and Engineering, Beihang University, Beijing 100083, China)

關鍵詞:

LY12鋁合金; 粗晶層; 應力腐蝕

DOI:

10.7502/j.issn.1674-3962.2013.03.06

文獻標志碼:

A

摘要:

以恒載荷應力腐蝕拉伸實驗，研究了具有粗晶層的LY12鋁合金在3��5 % NaCl+0��5 % H��2O��2溶液中的應力腐蝕行為。采用交流阻抗技術（EIS）分別對具有粗晶層和去除粗晶層后的LY12鋁合金試樣進行了電化學測試，利用掃描電鏡（SEM）和三維立體顯微鏡，系統觀察分析了合金試樣的顯微組織和應力腐蝕斷口形貌，分別計算了該合金試樣表層粗晶區和內層細晶區各自的晶粒度。結果表明，LY12鋁合金表層粗晶區的晶粒度等級為5��88，內層細晶區的晶粒度等級為12��71；粗晶區晶粒尺寸較大，對合金起到一定的保護作用，能夠顯著降低其應力腐蝕敏感性；帶有粗晶層的LY12鋁合金試樣交流阻抗譜阻抗半徑為2 500 Ω，去除粗晶層后，試樣的阻抗半徑下降至2 000 Ω。具有粗晶層的LY12鋁合金在3��5 % NaCl+0��5 % H��2O��2溶液環境中耐應力腐蝕性能更強。��

Abstract:

The stress corrosion cracking(SCC) behavior of LY12 alloy with coarse grained layer was investigated in 3 5 % NaCl+0��5 % H��2O��2 solution by constant load stress corrosion test  Electrochemical impedance spectroscopy (EIS) of the LY12 alloy with and without coarse�瞘rained layer was studied. The microstructure and fracture morphology were observed and analyzed by 3D�瞔ubic microscope and scanning electron microscope (SEM). The grain size of surface layer coarse grain zone and the inner layer fine zone of this alloy were calculated too. The results show that the grain size of coarse grain grade is 5��88, while that of inner zone is 12��71. Because grain size of coarse�瞘rain layer is bigger than the inner zone, the big size grains can protect the LY12 alloy from stress corrosion cracking and remarkably decrease the susceptibility of alloy from SCC in 3��5 % NaCl+0��5 %H��2O��2 solution. The impedance of the alloy with coarse�瞘rain layer is 2 500 Ω; after removing the coarse�瞘rain layer, the impedance declines to 2 000 Ω.