Pulsed laser polishing of selective laser melted aluminium alloy parts

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Pulsed laser polishing of selective laser melted aluminium alloy parts. / Bhaduri, Debajyoti; Ghara, Tina; Penchev, Pavel; Paul, Soumitra; Pruncu, Catalin; Dimov, Stefan; Morgan, David.

In: Applied Surface Science, Vol. 558, 149887, 30.08.2021.

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Bhaduri, Debajyoti ; Ghara, Tina ; Penchev, Pavel ; Paul, Soumitra ; Pruncu, Catalin ; Dimov, Stefan ; Morgan, David. / Pulsed laser polishing of selective laser melted aluminium alloy parts. In: Applied Surface Science. 2021 ; Vol. 558.

Bibtex

@article{b797414bf48449de88cc7ac5a5a2db54,
title = "Pulsed laser polishing of selective laser melted aluminium alloy parts",
abstract = "Laser polishing (LP) of aluminium alloys by re-melting is particularly challenging due to their high thermal conductivity, diffusivity and reflectivity. In this research, a novel LP strategy is proposed to improve material{\textquoteright}s re-melting by introducing a thermally insulating ceramic baseplate during nanosecond-pulsed laser polishing of selective laser melted (SLM) AlSi10Mg parts in atmospheric and argon environments. The strategy considerably improves the material{\textquoteright}s re-melting as realised via sub-surface temperature measurements. This leads to a substantial reduction in the average roughness Sa (by ~80-88%) and neutral/compressive residual stresses (up to −19 MPa) when polishing in air with a laser energy density of 12 J/cm2 and 10 scanning passes. In contrast, the unpolished SLM counterparts exhibit tensile stresses, up to +55 MPa. Laser polishing, however, somewhat reduces the Al parts{\textquoteright} bulk hardnesses (by ~15-25%) compared to the as-built specimens. Heat affected zones (HAZ) in the form of Al-rich white layers up to a depth of ~35 μm beneath the LP surfaces are observed on the cross-sectional microstructures. The study reveals the importance of controlling the heat dissipation from the objects when laser polishing of thermally conductive materials to achieve the desired surface integrity properties.",
keywords = "Laser polishing, Aluminium, Selective laser melting, Surface roughness, Residual stress, Microhardness",
author = "Debajyoti Bhaduri and Tina Ghara and Pavel Penchev and Soumitra Paul and Catalin Pruncu and Stefan Dimov and David Morgan",
year = "2021",
month = aug,
day = "30",
doi = "10.1016/j.apsusc.2021.149887",
language = "English",
volume = "558",
journal = "Applied Surface Science",
issn = "0169-4332",
publisher = "North-Holland Publ Co",

}

RIS

TY - JOUR

T1 - Pulsed laser polishing of selective laser melted aluminium alloy parts

AU - Bhaduri, Debajyoti

AU - Ghara, Tina

AU - Penchev, Pavel

AU - Paul, Soumitra

AU - Pruncu, Catalin

AU - Dimov, Stefan

AU - Morgan, David

PY - 2021/8/30

Y1 - 2021/8/30

N2 - Laser polishing (LP) of aluminium alloys by re-melting is particularly challenging due to their high thermal conductivity, diffusivity and reflectivity. In this research, a novel LP strategy is proposed to improve material’s re-melting by introducing a thermally insulating ceramic baseplate during nanosecond-pulsed laser polishing of selective laser melted (SLM) AlSi10Mg parts in atmospheric and argon environments. The strategy considerably improves the material’s re-melting as realised via sub-surface temperature measurements. This leads to a substantial reduction in the average roughness Sa (by ~80-88%) and neutral/compressive residual stresses (up to −19 MPa) when polishing in air with a laser energy density of 12 J/cm2 and 10 scanning passes. In contrast, the unpolished SLM counterparts exhibit tensile stresses, up to +55 MPa. Laser polishing, however, somewhat reduces the Al parts’ bulk hardnesses (by ~15-25%) compared to the as-built specimens. Heat affected zones (HAZ) in the form of Al-rich white layers up to a depth of ~35 μm beneath the LP surfaces are observed on the cross-sectional microstructures. The study reveals the importance of controlling the heat dissipation from the objects when laser polishing of thermally conductive materials to achieve the desired surface integrity properties.

AB - Laser polishing (LP) of aluminium alloys by re-melting is particularly challenging due to their high thermal conductivity, diffusivity and reflectivity. In this research, a novel LP strategy is proposed to improve material’s re-melting by introducing a thermally insulating ceramic baseplate during nanosecond-pulsed laser polishing of selective laser melted (SLM) AlSi10Mg parts in atmospheric and argon environments. The strategy considerably improves the material’s re-melting as realised via sub-surface temperature measurements. This leads to a substantial reduction in the average roughness Sa (by ~80-88%) and neutral/compressive residual stresses (up to −19 MPa) when polishing in air with a laser energy density of 12 J/cm2 and 10 scanning passes. In contrast, the unpolished SLM counterparts exhibit tensile stresses, up to +55 MPa. Laser polishing, however, somewhat reduces the Al parts’ bulk hardnesses (by ~15-25%) compared to the as-built specimens. Heat affected zones (HAZ) in the form of Al-rich white layers up to a depth of ~35 μm beneath the LP surfaces are observed on the cross-sectional microstructures. The study reveals the importance of controlling the heat dissipation from the objects when laser polishing of thermally conductive materials to achieve the desired surface integrity properties.

KW - Laser polishing

KW - Aluminium

KW - Selective laser melting

KW - Surface roughness

KW - Residual stress

KW - Microhardness

U2 - 10.1016/j.apsusc.2021.149887

DO - 10.1016/j.apsusc.2021.149887

M3 - Article

VL - 558

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

M1 - 149887

ER -