Functionally graded copper – steel using laser engineered net shaping™ process

Abstract

Laser Engineered Net Shaping™ (LENS™) is an emerging Solid Freeform Fabrication (SFF) process capable of producing fully dense metallic parts with complex shapes directly from a computer-aided drawing (CAD) without the need for molding or tooling. The LENS™ process also shows promise in producing components with graded compositions. One potential application is the production of steel – copper die casting materials. Copper is currently being considered for deposition on dies made out of steel to enhance thermal management. However, difficulties can occur at the Fe-Cu interface, such as, solidification cracking, formation of undesirable phases, and differences in coefficient of thermal expansion. The current research goal is to develop LENS™ processing parameters to optimize the deposition of functionally graded steel - Copper alloys. Dilution control experiments were carried out to determine the cracking susceptibility of Steel - Cu alloys of varying compositions. The resulting microstructures were characterized by various microscopy techniques. The influence of composition on the resultant cracking susceptibility and microstructure will be discussed. This information is useful for successful deposition of crack-free copper layers onto steel for die casting applications.