Modification of metal surfaces by the laser melt-particle injection process

Abstract

The laser melt-particle injection process was used to accomplish diverse modifications in the structure and chemistry of metal surfaces. This process consists in melting a shallow pool on the surface of a metal with a high power laser beam and injecting fine particles into the melt. In this paper we discuss wear-resisting surfaces produced by injecting TiC particles into the surfaces of 5052 aluminum and by surface alloying the same base metal with silicon. The operating conditions employed in the surface-alloying experiments were very similar to those used for carbide injection, but nearly complete dissolution of the injected silicon particles occurred during alloying while the injected carbide particles did not dissolve to any detectable degree. Previous experiments with this process have all been conducted at reduced pressure in an inert gas. The surface alloying and some of the carbide injection work described here were done at atmospheric pressure using a powder injection nozzle with inert gas shielding.