Effect of Ti on the Mechanical Properties and Corrosion of Cast AZ91 Magnesium Alloy

Ti addition to AZ91 alloy was been investigated with conventional casting. The microstructure and mechanical property were examined. The Corrosion resistance of all the different Ti addition content alloy was studied in 3.5% NaCl solution through weight loss measurement in constant immersion conditions and potentiodynamic polarization experiments. The results show that addition of Ti with an amount of 0.1~0.5%wt resulted in a refinement of the as-cast microstructure. The morphology of phases is changed from coarse, uneven, semi-continuous skeletal network to small, uniform, short rod-like or granular. When the content of Ti is 0.4wt%, the tensile strength and elongation go up to maximum value of 197 MPa and 6.9% respectively. The corrosion resistant improved through addition Ti element is related to the morphology and distribute of phases. The mechanism of mechanical properties and corrosion resistant improvement caused by Ti addition is discussed.