Thermal Behavior and Microstructural Evolution during Laser Deposition with Laser-Engineered Net Shaping: Part I. Numerical Calculations

Laser-engineered net shaping (LENS) is a rapid direct manufacturing process. The LENS process can be analyzed as a sequence of discrete events, given that it is a layer-by-layer process. The thermal history associated with the LENS process involves numerous reheating cycles. In this article, the thermal behavior during laser deposition with LENS is simulated numerically by using the alternate-direction explicit (ADE) finite difference method (FDM). The simulation results showed that deposited material experiences a significant rapid quenching effect during the initial stages of deposition and can attain a very high cooling rate. With an increase in deposit thickness, the rapid quenching effect decreases and eventually disappears. The effects of the processing parameters on the thermal behavior of deposited materials were also simulated and analyzed. The objective of this study is to provide insight into the thermal history during the LENS process, where the ability to correlate process parameters to microstructural evolution is a motivating force.