Thermal Behavior and Microstructure Evolution during Laser Deposition with Laser-Engineered Net Shaping: Part II. Experimental Investigation and Discussion

摘要

The thermal behavior during laser-engineered net shaping (LENS) processing was numerically simulated using the alternate direction explicit finite difference method in Part I of this work. In this article, Part II, the numerical simulation results were compared to experimental results obtained with LENS-deposited 316L stainless steel. In particular, the cooling rate that is present during LENS deposition was established on the basis of dendrite arm spacing (DAS) measurements with and without a melt pool sensor (MPS) and a Z-height control (ZHC) subsystem. The microstructure of the deposited materials was characterized and analyzed, and the corresponding microhardness was measured as a function of distance from the substrate. The influence of thermal history on microstructure evolution was analyzed and discussed based on both modeling and experimental results. The results discussed in this article suggest relatively good agreement between experiments and modeling.