Research On Plasma Surface Cr-Si Alloying And The Tribological Behavior Of Tial-based Alloy

TiAl-based alloy is one of the most competitive air titanium because of its specific strength, specific modulus, high temperature strength and so on. However, poor condition of air titanium especially when it was used in aircraft engine require superior wear resistance and high temperature oxidation resistance. The promotion of wear resistance and improvements of high temperature oxidation resistance have become crucial project problems.For solving the wear resistance problems of TiAl-based alloy at room and high temperature. Different wear resistant layers were prepared using double glow plasma surface alloying technique.The optimizing experiment were performed., Optical metallography(OM), scanning electron microscope(SEM), energy diffraction spectroscope(EDS), X-ray diffraction(XRD) were performed to study the phase formation and microstructure. Micro-hardness, scratching tester were performed to study micro-hardnss and bind strength. Wear resistance were tested by Friction and wear tester at room temperature. high temperature. High temperature oxidation resistance were tested.The optimizing results indicated that all of these Cr-Si duplex layers exceed 10μm. All the microhardness reached Hv1000. The content of Cr and Si decrease in gradient in the duplex layers. Type and relative content of phases were different from each other, but Si and Al-Cr compounds were the major phase of these layers. Metallurgical bond were emerged .Tribological test indicated that wear resistance of TiAl-based alloy have been enhanced rapidly at room and high temperature. Excellent wear resistance were displayed. Ti₅Si₃ ceramic layer,tough transition layer and high Si content contribute to wear resistance promotion .The results of oxidation experiment showed that not only wear resistance have been elevated, but also oxidation resistance have been improved.