Effects Of Rare Earth La On The Structure And Properties Of AZ91Magnesium Alloy

In this article, the effects of rare earth La and cooling speed on the structure andproperties of AZ91magnesium alloy were studied, and deformation behavior, oxidationand corrosion resistance properties of AZ91magnesium alloy were also studied by throughthe hot compress, high-temperature oxidation and corrosion experiment.The results showed that: AZ91magnesium alloy is made up of α-Mgå'ŒÎ²-Mg17Al12.When adding the rare earth La, there are needle Al11La3exhalation and the number of β-Mg17Al12will decrease. With the increase of the content of La, grain size of AZ91magnesium alloy from80.29μm reduce to66.88μm, detailing rate reached16.7%; thehardness, the tensile strength and elongation of magnesium alloy was changed Whenadding the rare earth La. In this study, when the content of La is0.9%, mechanical propertyis the best, hardness is84.18Hv, the strength of extension under room temperature is237MPa, elongation up to4.46%; the strength of extension in high temperature is154MPa,elongation up to8.6%.AZ91magnesium alloy showed a good anti-oxidation ability at410℃. With theincrease of the temperature, anti-oxidation ability will be decrease, when adding a amountof rare earth La, it can improve the anti-oxidation ability ofAZ91magnesium alloy.Strain rate of hot compression test is0.001～1/s, compression temperature is400℃，350℃and300℃, deformation is20%，10%，10%, total deformation is35.2%. With theincrease of the deformation，stress is also increase.Corrosion rate decreased of alloy with increasing content of rare earth La in the5%NaCl. When the content of La is1.2%, Corrosion rate of AZ91magnesium alloy isminimal.