Enhancing geometric integrity and surface hardness of SLM-printed Ti-6Al-4V components with support structures and laser nitriding
Year: 2024
Type: article
Abstract: This study investigated the effects of support structures and post-processing laser nitriding on high aspect ratio Ti-6Al-4V components fabricated using Selective Laser Melting (SLM). It examined changes in geometric integrity, porosity, and mechanical properties. Samples were printed without support structures (S1) and with support structures (S2). After SLM printing, both samples underwent open-air laser nitriding at duty cycles (DC) ranging from 50% to 100%, aiming to create crack-free nitride layers to increase surface hardness. The results indicated that support structures effectively mitigate thermal-induced deformation, with S2 exhibiting minimal warping and closer adherence to design specifications than S1. Although S2 showed increased porosity as revealed by X-ray Computed Tomography (XCT), its refined microstructure contributed to increased hardness. Optical Microscope and Scanning Electron Microscope (SEM) analyses demonstrated that laser nitriding at a 50% duty cycle produced uniform, crack-free titanium nitride (TiN) layers. Vickers hardness tests revealed a significant enhancement in the surface hardness of both laser-nitrided samples, with S2 displaying finer TiN dendrites that further improved its surface hardness. The use of support structures was found to be effective in achieving a more uniform microstructure and enhanced hardness in the nitride layers.
Source: Surface and Coatings Technology
Authors: Weijie Xie, Conall Kirk, Amal Rejee, Hau-Chung Man, Chi-Wai Chan
Institutions: Queen's University Belfast, Hong Kong Polytechnic University
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,770
Award: G6800325384
OpenAlex ID: W4402618285