Hard surfacing of TiAl intermetallic compound by plasma carburization

For an intermetallic compound such as TiAl to be used in various components, the wear resistance is very important. Recently, plasma carburization was performed on the fully lamellar cast alloy with Ti-33.5Al-1Nb-0.5Cr-0.5Si (mass%). The induced surface layer, 3 mu m in thickness, was a carbide, Ti2AlC, with a hardness that was higher than HV836 for a bearing steel AIS152100. The pin-on-disk test showed that the carburized pins possessed excellent wear resistance against the steel disk. The carburization did not cause deterioration of the tensile and fatigue properties at room temperature. Therefore, the plasma carburization is regarded as one of the promising technologies for improving the wear resistance of TiAl.