Multicycle Surface Alloying of Aluminum with Titanium: Structure and Properties

Abstract

Commercially pure A7 aluminum was surface alloyed with commercially pure titanium on COMPLEX equipment under unified vacuum conditions through vacuum arc evaporation and deposition of a thin Ti film and intense electron beam irradiation of the film–substrate system using a plasma-cathode pulsed electron source. The number of deposition–irradiation cycles was 20. The Ti film thickness in each cycle was 0.5 μm. After multicycle alloying, a modified surface layer of up to 60 μm thick was formed representing a multiphase structure of rapidly solidified submicro-and nanograins. The microhardness of the Ti–Al surface alloy (irradiation at 15 J/cm2, 50 μs, 10 pulses) was more than 8 times the microhardness of A7 aluminum, and its wear resistance and friction coefficient were respectively 45 times higher and 1.2 times lower than the values in the initial material. The chief cause for the improved mechanical and tribological properties of commercially pure A7 aluminum is the formation of an extended intermetallic layer.