Study on Modification of TiAl Alloy for Automotive Turbocharger

The Ti-47.5Al-2.5V-1Cr-0.1Y alloy samples for automobile turbocharger were respectively prepared by common casting and two-step method,and the microstructures,mechanical properties,corrosion resistance and fatigue resistance for the samples by the 2 methods mentioned above were tested and contrastively analyzed.The results show that the crystalline grain can be refined and the casting defects such as pores and microporosity are avoided,and the mechanical properties,corrosion resistance and fatigue resistance of the alloy are improved by two-step method,compared to the common casting method.For sample prepared by the two-step method,the tensile strength and impact absorbing energy at room temperature respectively increases by 33.28% and 33.33%,the fatigue life increases by 95.34% and the corrosion potential changes 236 mV to the positive direction.