A surface treatment for a class of metallic articles is described. The treatment involves the melting of a thin surface layer of the article by a concentrated energy source, within a narrow set of parameters. The melting step is performed in a manner which maximizes the temperature gradient between the melted and unmelted portion of the article, consequently, cooling and solidification upon the removal of the energy source is extremely rapid and can produce unique microstructures. The preferred energy source is a continuous wave laser, and in the preferred embodiment, a flowing inert gas cover is used to minimize melt contamination and plasma formation. The technique may be used to produce amorphous surface layers in a specific class of eutectic alloys. In another class of alloys, based on the transition metals and containing precipitates rich in one or more metalloids, uniquely fine microstructures may be produced.
A method of irradiating a metal piece (5) with a laser beam for generating a metal vapor (11) required for a metal vapor laser to oscillate. The method makes it possible to reduce the time required to activate the laser as well as the response time required to adjust the metal vapor density. Metals having a high melting point can also be vaporized for laser oscillation in accordance with the method.
This marking method is carried out with an object to form a mark of high visibility on a surface of a metallic layer of such as a cover plate of a semiconductor device or the like without generating metallic debris or the like. According to this method, on a marking area of a metallic layer with a matte surface (R.sub.max :0.5 to 5 .mu.m), a laser beam is illuminated, thereby the metallic layer is melted, then re-solidified, thereby minute unevenness on the surface of the metallic layer is averaged and erased to be smooth. Thus formed marking portion reflects light specularly and is different in light reflectivity from an underlying portion which scatters light (diffuse reflection). Due to the difference of reflectivity, the marking portion can be visually discerned with excellency.
An apparatus and process for improving the microstructure of electrically conducting materials is disclosed by the present invention. A revolving heat source applies heat to the surface of the material evenly and quickly. One or more heat sinks quickly cool the material. In the preferred embodiment, the cooling may be done in such a way as to promote as high a degree of directional grain growth as desired or completely nondirectional grain growth.
An amorphous metal having a desired irregularity is formed by irradiating a metal with an electron beam having an energy large enough to damage the metal thereby introducing a lattice defect into the metal and controlling the concentration of the introduced lattice defect.
A desired shape of amorphous region is formed at a predetermined position in a metal crystal by introducing the desired shape of lattice defect at the predetermined position in the metal crystal, and then irradiating the lattice defect with an electron beam to form the desired shape of amorphous region at the predetermined position in the metal crystal.
