Influence of laser powder bed fusion scanning pattern on residual stress and microstructure of alloy 718Show others and affiliations
2022 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 221, article id 110983Article in journal (Refereed) Published
Abstract [en]
A comprehensive investigation is undertaken on the effect of laser scanning pattern on the microstructure of cylindrical samples made of Alloy 718 processed by Laser Powder Bed Fusion. It is observed that the common alternate direction scanning of the laser results in a more homogeneous microstructure than the less common concentric line scans where significant microstructural heterogeneities are seen between the edges and the center of the sample. The investigation focuses on the precipitation, crystallographic texture, grain size, grain morphology and residual stresses utilizing synchrotron X-ray diffraction, neutron diffraction and electron microscopy. The heterogeneous microstructure of the sample processed with the concentric laser pattern influences the chemical composition of the matrix, which alters the reference “strain free” interplanar spacing used for evaluating the residual strain. The investigation underlines the significance of the processing parameters on the homogeneity of the microstructure and the effect of the chemical variations on the determination of residual stresses in materials such as Alloy 718, where strong local chemical variations occur because of different types and extent of precipitation. © 2022
Place, publisher, year, edition, pages
2022. Vol. 221, article id 110983
Keywords [en]
Morphology; Neutron diffraction; Precipitation (chemical); Scanning; Selective laser melting; Superalloys; Textures; Alloy 718; Chemical variations; Cylindrical samples; Homogeneous microstructure; Laser pattern; Laser powders; Laser scanning; Line scan; Powder bed; Selective laser melting; Residual stresses
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
URN: urn:nbn:se:hv:diva-19171DOI: 10.1016/j.matdes.2022.110983Scopus ID: 2-s2.0-85135381018OAI: oai:DiVA.org:hv-19171DiVA, id: diva2:1709323
Note
financial support from the Strategic Focus Area Advanced Manufacturing (SFA-AM) initiative of the ETH Board
2022-11-082022-11-082022-11-08