(1.Shenyang Aircraft Design & Research Institute, Shenyang 110035, China) (2.School of Materials Science and Engineering, Beihang University, Beijing 100083, China)
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DOI:
10.7502/j.issn.1674-3962.2013.03.06
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Abstract:
The stress corrosion cracking(SCC) behavior of LY12 alloy with coarse grained layer was investigated in 3 5 % NaCl+05 % H2O2 solution by constant load stress corrosion test Electrochemical impedance spectroscopy (EIS) of the LY12 alloy with and without coarsegrained layer was studied. The microstructure and fracture morphology were observed and analyzed by 3Dcubic 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 588, while that of inner zone is 1271. Because grain size of coarsegrain 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 35 % NaCl+05 %H2O2 solution. The impedance of the alloy with coarsegrain layer is 2 500 Ω; after removing the coarsegrain layer, the impedance declines to 2 000 Ω.