Modification of titanium surface by its alloying with silicon using intensive pulsed plasma beams

Surface alloying of Ti with Si has been performed with the use of high intensity pulsed plasma beams. In this technique, short, intense (1 µs, 3-4 J/cm²) plasma pulses serve as a source of heat to melt the near surface layer (up to 2 µm) of the Ti substrate togehter with a Si film (30 and 70 µg/cm²) pre-deposited on it. In the molten state, lasting a couple of microseconds, rapid diffusion of Si into Ti occurs leading to formation of new phases during rapid solidification of the molten surface layer. In the present work, an attempt has been undertaken to improve the mechanical properties of titanium via precipitation of hard stable phases in the Ti-Si system, is formed by the transient heat treatment. During subsequent annealing for 1 h at 800°C a fraction (14-43%) of Ti₅Si₃ transforms into TiSi. The presence of silicide precipitates in the near surface region layer of titanium increases dramatically its wear resistance.