Abstract
To increase building rate and save cost, the selective laser melting (SLM) of Ti6Al4V with a high layer thickness (200 μm) and low cost coarse powders (53 μm–106 μm) at a laser power of 400 W is investigated in this preliminary study. A relatively large laser beam with a diameter of 200 μm is utilized to produce a stable melt pool at high layer thickness, and the appropriate scanning track, which has a smooth surface with a shallow contact angle, can be obtained at the scanning speeds from 40 mm/s to 80 mm/s. By adjusting the hatch spacings, the density of multi-layer samples can be up to 99.99%, which is much higher than that achieved in previous studies about high layer thickness selective laser melting. Meanwhile, the building rate can be up to 7.2 mm3/s, which is about 2 times–9 times that of the commercial equipment. Besides, two kinds of defects are observed: the large un-melted defects and the small spherical micropores. The formation of the un-melted defects is mainly attributed to the inappropriate overlap rates and the unstable scanning tracks, which can be eliminated by adjusting the processing parameters. Nevertheless, the micropores cannot be completely eliminated. It is worth noting that the high layer thickness plays a key role on surface roughness rather than tensile properties during the SLM process. Although a sample with a relatively coarse surface is generated, the average values of yield strength, ultimate tensile strength, and elongation are 1050 MPa, 1140 MPa, and 7.03%, respectively, which are not obviously different than those with the thin layer thickness used in previous research; this is due to the similar metallurgical bonding and microstructure.
Highlights
Selective laser melting (SLM) is one of the additive manufacturing techniques in which functional, complex parts are formed by selectively melting successive layers of powder particle using a laser beam
The properties of the parts manufactured by selective laser melting (SLM) depend strongly on the properties of each single track
Selective laser melting technology has been used to build Ti6Al4V samples by melting coarse powder ranging from 53 μm to 106 μm in a thicker powder layer of 200 μm
Summary
Selective laser melting (SLM) is one of the additive manufacturing techniques in which functional, complex parts are formed by selectively melting successive layers of powder particle using a laser beam. During the SLM processing, the layer thickness is very thin, about 20 μm–50 μm [5,6,7,8,9], which results in the high surface precision. For some metal parts of which the surface finish requirements are relatively low, high layer thickness can be applied to increase the building rate. For some metal parts of which the surface finish requirements are relatively low, high layer thickness. Demonstrated that high layer thickness is an effective way to improve SLM process efficiency. In this paper, the SLM with high layer thickness (200 μm) and coarse powders The SLM processing is systematically investigated to obtain high which is necessary for high mechanical properties. The formation mechanisms of defects are morphology revealed. with different process parameters and the formation mechanisms of defects are revealed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
