Influence Of Carbon Content On Mechanical Property And Corrosion Performance Of Magnesium Alloy

At present, magnesium alloys have been widely applied in aerospace, petroleum, and other fields, fully reflecting the value of engineering materials with rich resources, low density and high specific strength. Magnesium alloys have good room temperature strength,resistance to corrosion and other excellent characteristics, but their low high-temperature strength and poor plasticity limit their further applications. In this paper, adding alloying element C in a magnesium alloy was employed to refine alloy particles and alloy microstructure so as to improve the alloy high temperature strength and plasticity, the carbon as cathode material to achieve the rapid dissolution of magnesium alloy.In this paper, the alloying element C(0-0.5 wt.%) was added in a magnesium alloy by a high temperature melting process and the influence of C content(C%) on the microstructure morphology, comprehensive mechanical properties and corrosion resistance of the magnesium alloy was studied using emission spectrum, metallographic microscope,universal testing machine, thermal simulation compression tests and electrochemical tests.The involved mechanisms were discussed too. The results indicate that the remelting process can make the crystalline of the raw magnesium alloy change from a coarse dendrite distribution to a continuous mesh distribution. With the addition of carbon, the grain size of the magnesium alloy is obviously refined and distributed evenly. With an increase in the C content(C%), the grain size of the magnesium alloys decreases firstly and then increases,while the mechanical and plastic properties of the magnesium alloy increases firstly and then decreases. When C% = 0.2%, the magnesium alloy shows the best mechanical properties,such as the tensile strength = 229 MPa and the compressive strength = 337 MPa at room temperature, while the tensile strength = 230 MPa and the compressive strength = 296 MPa at 150 ?. When C% = 0.2% and T=150?, the compressive strength = 268 MPa. With an increase in temperature(T), the mechanical properties of the magnesium alloy generally decreases and the plastic properties increases.The corrosion rate of the remelted magnesium alloy reduces, suggesting that the corrosion resistance of the magnesium alloy is improved by the remelting process.With an increase in C% and T, the corrosion rate of the magnesium alloy gradually increases and reaches the maximum value(17.28 mm/a) when C%=0.5% and T=90 ?.The increase of C% in themagnesium alloy accelerates its corrosion significantly. With an increase in C% and T, the weight loss rate and the galvanic corrosion rate of the magnesium alloy also gradually increases. The galvanic corrosion rate is much larger than that of the weight loss rate and reaches the maximum value(521.2 mm/a) when C%=0.5% and T=90 ?. The rapid dissolution of the magnesium alloy is realized.Based on the above experimental results, when C%=0.5%, the magnesium alloy can not only meet the requirements of high temperature mechanical properties, but also meet the requirements of the rapid dissolution of magnesium alloy.