Partner: Paul Wood |
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Recent publications
1. | Kopeć M., Dubey Ved P., Pawlik M.♦, Wood P.♦, Kowalewski Z.L., Experimental identification of yield surface for additively manufactured stainless steel 316L under tension–compression-torsion conditions considering its printing orientation, Manufacturing Letters, ISSN: 2213-8463, DOI: 10.1016/j.mfglet.2024.07.003, Vol.41, pp.28-32, 2024 Abstract: Stainless steel 316L tubes and bars were additively manufactured (AM) by using the Laser Powder Bed Fusion Melting (LPBF-M) method in three orientations. As-built specimens were then machined and the initial yield surface was determined for three printing orientations based on the yield stress definition for 0.005 % plastic offset strain. The as-received, wrought material was additionally tested using the same tension–compression-torsion conditions to compare the mechanical behaviour of AM and wrought SS316L. The sizes of yield surfaces elaborated for LPBF-M specimens increased along the tensile and compressive directions and shrunk when torsion was applied, as compared to the as-received specimen. Keywords:Stainless steel ,Yield surface ,Additive manufacturing Affiliations:
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2. | Kopeć M., Gunputh U.♦, Williams G.♦, Macek W.♦, Kowalewski Z.L., Wood P.♦, Fatigue Damage Evolution in SS316L Produced by Powder Bed Fusion in Different Orientations with Reused Powder Feedstock, EXPERIMENTAL MECHANICS, ISSN: 0014-4851, DOI: 10.1007/s11340-024-01118-1, pp.1-16, 2024 Abstract: Background SS316L ,Stainless steel,Fatigue ,Additive manufacturing,Laser Powder Bed Fusion Melting (LPBF-M) Affiliations:
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3. | Kopeć M., Gunputh U.♦, Macek W.♦, Kowalewski Z.L., Wood P.♦, Orientation effects on the fracture behaviour of additively manufactured stainless steel 316L subjected to high cyclic fatigue, Theoretical and Applied Fracture Mechanics, ISSN: 0167-8442, DOI: 10.1016/j.tafmec.2024.104287, pp.1-20, 2024 Abstract: In this paper, stainless steel 316L (SS316L) bars were additively manufactured (AM) in three orientations (Z – vertical, XY – horizontal, ZX45 – midway between vertical and horizontal) by using the Laser Powder Bed Fusion Melting (LPBF-M) method. The AM specimens were subjected to load control fatigue testing under full tension and compression (R = -1) at stress amplitudes ±350, ±400 and ±450 MPa. The XY and ZX45 printing orientations were found to significantly improve service life. Although similar strain response was found for each orientation when the same stress amplitude was applied, slightly different fracture mechanisms were identified during the post-mortem surface observations. Keywords:SS316L,stainless steel,fatigue,additive manufacturing,Laser Powder Bed Fusion Melting (LPBF-M) Affiliations:
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4. | Wood P.♦, Libura T., Kowalewski Z.L., Williams G.♦, Serjouei A.♦, Influences of horizontal and vertical build orientations and post-fabrication processes on the fatigue behavior of stainless steel 316L produced by selective laser melting, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244203, Vol.12, No.24, pp.4203-1-19, 2019 Abstract: In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems. Keywords:selective laser melting, stainless steel 316L, fatigue, defect, fracture Affiliations:
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Conference abstracts
1. | Dubey V.P., Kopeć M., Pawlik M.♦, Wood P.♦, Kowalewski Z.L., Effect of Build Orientation on the Yield Surface of Stainless Steel 316L Fabricated by Laser Powder Bed Fusion Melting (LPBF-M), BSSM, 18th International Conference on Advances in Experimental Mechanics, 2024-09-03/09-05, Liverpool (GB), pp.1-2, 2024 Abstract: The Laser Powder Bed Fusion Melting (LPBF-M) method was used to additively manufacture stainless steel 316L tubes in three different orientations. The yield surface approach was implemented to assess the variation of mechanical properties within the as-built specimens. Yield surfaces were determined for each build orientation based on the definition of yield stress for 0.005% plastic offset strain. The initial yield surfaces obtained for the as-built material exhibit anisotropic behaviour, possibly resulting from the preferred grain orientation developed during LPBF-M processing. Affiliations:
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2. | Wood P.♦, Gunputh U.♦, Williams G.♦, Carter W.♦, Boud F.♦, Bahi S.♦, Rusinek A., Kowalewski Z.L., Nowak Z., Libura T., Vojiadjis G.Z.♦, Diaz-Alvare J.♦, Miguelez M.H.♦, SELECTIVE LASER MELTING OF A HIGH PRECISION TURBOMACHINERY APPLICATION IN IN718 ALLOY, ICEM, 19th International Conference on Experimental Mechanics, 2022-07-17/07-21, Kraków (PL), pp.34-35, 2022 |