This technical presentation reviews collaboration between AlphaSTAR Technology Solutions and Penn State University Materials Science and Engineering Department. Special thanks to NCDMM and The Manufacturing Technology Defense Group for their support of this project.

Abstract

Integrated Computational Materials Engineering (ICME) technology has been test-validated to optimize the process parameters for Selective Laser Melting (SLM) of AlSi10Mg to achieve minimum porosity for multiple additively manufactured (AM) parts. An experimental study of the effects of AM process parameters on porosity and strength of sixty AlSi10Mg specimens is used for test validation of ICME simulations over a wide range of values for laser power and laser speed. New ICME technology is capable of generation of G-code, print path coverage, microscale simulations of thermal states, selective melting of AlSi10Mg powder, and prediction of meltpool size and microscale porosity for sixty specimens in one build volume. ICME technology is used to generate a process map and a void map for different laser power and speed to perform meltpool engineering and identify optimal process parameters with minimum AM defects and lack of fusion (LOF). The process void map demonstrates the existence of a distinct region associated with significantly higher porosity for high values of laser power and low laser speed, which is characterized by higher laser energy density. The critical value of laser energy density is found to be the key physical parameter associated with the increased porosity in AM parts. Numerical predictions of microscale porosity have been successfully test-validated by a close comparison of virtual AM simulations to experimental results. Design of Experiment (DoE) optimization of processing parameters for SLM of AlSi10Mg powder for minimum porosity has been carried out with a surrogate model based on experimental data. Optimized values of AM process parameters are close to the optimal laser power and speed identified by experimental data. Sensitivity of porosity to variations of laser power and speed, and hatch spacing has been analyzed.


Keywords: 1) Integrated Computational Materials Engineering (ICME), 2) SLM, 3) process map, 4) AlSi10Mg, 5) meltpool engineering, 6) lack of fusion.