Evaluation of the microstructure and physical properties of metallic materials treated with pulsed, intense ion beams

Summary form only given. The authors discuss recent work on characterizing metals exposed to single and multiple pulses from high-energy ion-beams (300 keV to 1 MeV) composed of protons or a mixture of protons and C. Exposure of 0-1 tool steel to a single pulse of a 1-MeV ion beam (proton + C) at a energy density of 5 J/cm/sup 2/ resulted in the melting and resolidification of the top seven microns of the material. Transmission electron microscopy, X-ray diffraction, and optical metallography analyses of the treated surface showed that ion beam treatment resulted in the transformation of a large grained, equilibrium carbide and bcc (body centered cubic) iron microstructure to a mixture of fine-grained carbide, bcc iron, and metastable fcc (face centered cubic) iron. The transformation of the microstructure was accompanied by a three-fold increase in the nominal surface hardness. In addition, scanning electron microscopy shows that the surface of a roughened commercial Ti-Al-V alloy was significantly smoothed by exposure to a single pulse of a 1-MeV proton beam.