Research on Stress Corrosion Behavior of AZ91 Magnesium Alloy Modified by Erbium and Cerium
Abstract
AZ91magnesium alloys modified by erbium (Er) and cerium (Ce) (AZErCe)were fabricated by casting into metal mold. The effect of Er and Ce on the microstructure and stress corrosion cracking (SCC) behavior of AZ91 in Cl- containing moist atmosphere was investigated by slow strain rate tensile (SSRT) tests, potentiodynamic polarization analysis, X-ray photoelectron spectroscope (XPS), scanning electron microscope (SEM) and X-ray diffraction (XRD). The results showed that the β-Mg17Al12 phase was transformed from discontinuous network into small island distribution and dispersed homogeneously after the addition of Er and Ce, and the formation of Al3Er and Al11Ce3 intermetallic compounds reduced the volume fraction of β-Mg17Al12 phase.The addition of Er and Ce greatly improved the SCC resistance, because the local corrosion resistance of AZErCe was improved by alleviating the cathodic effect of β-Mg17Al12 phase and improving the compactness of the surface films. As a result, the processes of initiation and expansion of cracks were suppressed and the influence of hydrogen embrittlement on SCC resistance was weakened. The fractography of SCC was changed from brittle cleavage fracture into quasi-cleavage fracture, and the local corrosion at the edge of fracture surfaces was greatly alleviated.
Keywords: magnesium alloy, erbium, cerium, stress corrosion cracking, fracture morphology
Full Text:
PDFReferences
ATRENS A, SONG G -L, LIU M, et al. Review of recent development in the filed of magnesium corrosion) J J. Advanced Engineering Materials. 2015, 17(4) : 400 - 453.
WINTER N. ATRENS A. SONG G -L. et al. A critical review of the stress corrosion cracking (SCС) of magnesium alloys [J]. Advanced Engineering Materials, 2005, 7(8) : 659 - 693.
PADEKAR B S, SINGH RAMAN R K, RAJA V S. et al. Stress corrosion cracking of a recent rareearth containing magnesium alloy, EV31 A, and a common Al-containing alloy, AZ91E [JJ. Corrosion Science, 2013, 71(6); 1 -9.
BOBBY KANNAN M, DIETZEL W, BLAWERT1 C, et al. Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80[j]. Materials Science and Engineering A, 2008, 480 (1): 529-539.
MERT F. BLAWERT C. KAINER K U,et al. Influence of cerium additions on the corrosion behaviour of high pressure die cast ËÌ50 alloy [j]. Corrosion Science. 2012. 65(2): 145 -151.
LIU G L. Electronic theoretical study on the influence of rare earth on the stress corrosion in magnesium alloy [j]. Acta Physica Sinica. 2006. 55(12): 6570 - 6573. (In Chinese)
SONG Y L, LIU Y II. WANG S H. et at. Effect of cerium addition on microstructure and corrosion resistance of die cast AZ91 magnesium alloy[.L. Materials and Corrosion. 2007. 58 (3): 189-192.
AMBAT R. AUNG N. ZHOU W. Evaluation of microstructural effects on corrosion behaviour of AZ91I) magnesium alloy [j]. Corrosion Science. 2000. 42(8): 1433-1455.
MOODY N R. THOMPSON A W. RICKER R E. et al. Hydrogen effects on materials behavior and corrosion deformation interactions [J]. USA: The Minerals. Metals 2- Materials Society. 2003: 449-466.
BOBBY KANNAN M. D1ETZEL W. Fitting-induced hydrogen embrittlement of magnesium-aluminum alloy [J]. Materials and Design. 2012. 12: 321-326.
Refbacks
- There are currently no refbacks.