FORMATION OF METALLIC GLASS COATINGS VIA LASER DEPOSITION

摘要

Metallic glasses have attracted tremendous attentionrnas structural materials because of their remarkablernmechanical and corrosion properties. Laserrndeposition is a useful technique to create and producerncoatings with amorphous or uniquely tailored, nonequilibriumrnmicrostructures. In this study, we use thernLaser Engineered Net Shaping (LENS?) process torndeposit pre-alloyed Zr-based and Cu-based metallicrnglass forming powder on the Zr-based glassyrnsubstrates. In both cases, amorphous melt zones arernobserved surrounded by crystalline heat-affectedrnzones (HAZs). The microstructures of the depositedrnmaterials and underlying substrates were analyzedrnand characterized as functions of the laser processingrnparameters. To better understand the thermalrnenvironment for the formation of metallic glassrncoatings via laser deposition, a three-dimensionalrnfinite element model was performed and comparedrnwith the in-situ thermal imaging measurements. It isrnindicated that optimization of the laser energy inputrncan result in the formation of a continuousrnamorphous layer with the elimination of underlyingrncrystalline HAZs.