Irradiation of titanium was performed with high power electron beams. The e
lectron energy was 800 keV, the pulse duration was 10 ns and energy density
injected into the sample by one pulse was 20 J cm(-2). Hardness measuremen
ts of irradiated samples permit the detection of two different modified lay
ers. The hardness of these two layers depends on the pulse number. The stat
es of stress and the grain size in irradiated samples were determined by X-
ray diffraction. XRD shows the presence of the high pressure omega phase in
titanium after power electron beam exposure. The explanation of the result
s is based on stress waves, which arise due to such exposures. The observed
hardening of irradiated titanium is a result of an intensive process of tw
inning produced by shear stress waves. (C) 1999 Elsevier Science S.A. All r
ights reserved.