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| 2. |
- Čapek, J., et al.
(författare)
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Influence of laser powder bed fusion scanning pattern on residual stress and microstructure of alloy 718
- 2022
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Ingår i: Materials & design. - : Elsevier Ltd. - 0264-1275 .- 1873-4197. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 4. |
- Jenkins, Samantha, 1967-, et al.
(författare)
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The chemical character of very high pressure ice phases.
- 2006
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Ingår i: Proceedings of the 11th International Conference on the Physics and Chemistry of Ice. - Cambridge : RSC publishing. - 9780854043507 ; , s. 265-273
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Jenkins, Samantha, 1967-, et al.
(författare)
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Topological transitions between ice phases.
- 2006
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Ingår i: Proceedings of the 11th International Conference on the Physics and Chemistry of Ice. - Cambridge : RSC publishing. - 9780854043507 ; , s. 249-257
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Yehorov, Yurii, et al.
(författare)
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Exploring the use of switchback for mitigating homoepitaxial unidirectional grain growth and porosity in WAAM of aluminium alloys
- 2019
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Ingår i: The International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 104:1-4, s. 1581-1592
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Tidskriftsartikel (refereegranskat)abstract
- In this work, an alternative approach to prevent unidirectional grain growth in wire + arc additive manufacturing (WAAM) is proposed and assessed, by moving cyclically the torch forward and backward, likewise the welding technique known as switchback. A series of tests were planned with CMT (cold metal transfer) process to compare three wall-like build-ups, which uses different deposition patterns, namely, in one-way direction, reverse direction, and switchback. The same equivalent travel speed and number of deposited layers were kept among them. Longitudinal sections were taken to identify the grain growth behaviour. Finally, samples were removed from the walls for porosity evaluation. The results confirmed the characteristics of unidirectional grain growth, when one-way direction condition was employed, and the break of growth direction between layers, when reverse direction was used, yet a zig-zag pattern became present. Differently, the application of switchback showed no preferential or unidirectional grain growth, suggesting less anisotropy of mechanical properties. In addition, switchback reduced porosity. © 2019, The Author(s).
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