Influence of the β-Mg17Al12 Phase Morphology on the Corrosion Properties Of Az91hp Magnesium Alloy

International Conference on Materials Sciences and Nanomaterials

材料科学;物理学

Guo, Lingling^1 ; Zhang, Jumei^1

School of Materials Science and Engineering, Xi'An University of Science and Technology, Xi'an

710054, China^1

关键词: Cast magnesium alloy;    Corrosion barriers;    Corrosion propagation;    Corrosion property;    Isothermal process;    Polarization measurements;    Spherical morphologies;    Spheroidizing treatment;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/230/1/012009/pdf
DOI  :  10.1088/1757-899X/230/1/012009

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The morphology of β-Mg17Al12phase and corrosion behavior of AZ91HP magnesium alloy after spheroidizing treatment were investigated by optical microcope electrochemical and immersion tests in 3.5% NaCl at 25°C. The results show that the coarse divorced eutectic phase of AZ91HP cast magnesium alloy dissolve into Mg matrix during the isothermal process at 415°C, and the lameller β phase precipitated from magnesium solid solution as perlite-type precipitation during the slowly cooling. Next, the spheroidizing treatment at different temperatures for 20h was carried out, and the lameller β phase were spheroridizing by dissolved themselves. After spheroidizing treatment at 300°C for 20h, many small granular β phase are scattering within the magnesium matrix. The corrosion properties of AZ91HP magnesium alloy in 3.5% NaCl decreased obviously after spheroidizing treatment, the polarization measurement of the alloy can be up to -1.412V from -1.56V of the cast. The β-Mg17Al12phase act as a corrosion barrier and hinder corrosion propagation, if the second phase is in the form of a spherical morphology.