Karolien Kempen

Processing AlSi10Mg by selective laser melting: parameter optimisation and material characterisation

Abstract Owing to their attractive combination of mechanical properties, high heat conductivity and low weight, the Al–Si alloys found a large number of applications in the Additive Manufacturing field for automotive, aerospace and domestic industries. However, due to their high reflectivity and heat conductivity, they are harder to process by Selective Laser Melting. This work elaborates on both the optimisation of process parameters, in order to get nearly fully dense parts, and the material properties resulting from this specific material process combination. A process parameter window is defined, in which the formed melt pool is stable and meets the set requirements. In this process window, the parameter set for optimal density is defined. It is shown that AlSi10Mg parts produced by SLM have mechanical properties higher or at least comparable to the cast material because of the very fine microstructure.

Optimization of Scan Strategies in Selective Laser Melting of Aluminum Parts With Downfacing Areas

Selective laser melting (SLM) is an additive manufacturing technique in which metalproducts are manufactured in a layer-by-layer manner. One of the main advantages ofSLM is the large geometrical design freedom. Because of the layered build, parts withinner cavities can be produced. However, complex structures, such as downfacing areas,influence the process behavior significantly. The downfacing areas can be either horizon-tal or inclined structures. The first part of this work describes the process parameter opti-mization for noncomplex, upfacing structures to obtain relative densities above 99%.Inthe second part of this research, parameters are optimized for downfacing areas, bothhorizontal and inclined. The experimental results are compared to simulations of a ther-mal model, which calculates the melt pool dimensions based on the material properties(such as thermal conductivity) and process parameters (such as laser power and scanspeed). The simulations show a great similarity between the thermal model and the actualprocess. [DOI: 10.1115/1.4028620]Keywords: SLM, AlSi10Mg, downfacing structures

Selective Laser Melting of Crack-Free High Density M2 High Speed Steel Parts by Baseplate Preheating

Cracks and delamination, resulting from residual stresses, are a barrier in the world of additive manufacturing and selective laser melting (SLM) that prohibits the use of many metals in this field. By preheating the baseplate, thermal gradients are lowered and stresses can be reduced. In this work, some initial tests were performed with M2 high speed steel (HSS). The influence of preheating on density and mechanical and physical properties is investigated. The paper shows many promising results for the production of SLM parts in materials that are very sensitive to crack formation and delamination. When using a preheating of 200 � C, crack-free M2 HSS parts were produced with a relative density of 99.8%. [DOI: 10.1115/1.4028513]