[en] While it is generally accepted that the rupture of SLM AlSi10Mg tensile specimens occurs at the melt pool boundary, the exact zone and microstructural features responsible for the rupture have not been clearly identified. In this study, the microstructures and local mechanical properties at the melt pool boundary are thus analyzed in details. The Si phase fraction and the Si precipitate spacing are measured by image analysis and SEM-EDS analysis. Hardness tests are performed by nanoindentation. Fracture features are observed on broken samples. It is found that the Heat Affected Zone (HAZ) exhibits low hardness due to coarse non-coherent Si precipitates. Void nucleation occurs at the interface between the coarse Si precipitates and the Al matrix by dislocations piling up. For that reason, the HAZ is found to be the preferential region where fracture is likely to occur. This analysis is confirmed by the matching of Si precipitate spacing within the HAZ with dimple spacing observed in fracture surfaces. Moreover, a simple analytical approach of the thermal history during manufacturing, using Rosenthal’s equation, allows elucidating the mechanisms by which the processing conditions affect the fracture behavior.
Disciplines :
Materials science & engineering
Author, co-author :
Delahaye, Jocelyn ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > Science des matériaux métalliques
Tchuindjang, Jérôme Tchoufack ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > Science des matériaux métalliques
Lecomte-Beckers, Jacqueline ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > Science des matériaux métalliques
Rigo, Olivier; Sirris Research Centre
Habraken, Anne ; Université de Liège - ULiège > Département ArGEnCo > Département ArGEnCo
Mertens, Anne ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > Science des matériaux métalliques
Language :
English
Title :
Influence of Si precipitates on fracture mechanisms of AlSi10Mg parts processed by Selective Laser Melting
Publication date :
15 August 2019
Journal title :
Acta Materialia
ISSN :
1359-6454
eISSN :
1873-2453
Publisher :
Elsevier, Netherlands
Volume :
175
Pages :
160-170
Peer reviewed :
Peer Reviewed verified by ORBi
Name of the research project :
Iawatha
Funders :
FEDER - Fonds Européen de Développement Régional [BE] F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
Kimura, T., Nakamoto, T., Microstructures and mechanical properties of A356 (AlSi7Mg0.3) aluminum alloy fabricated by selective laser melting. Mater. Des. 89 (2016), 1294–1301, 10.1016/j.matdes.2015.10.065.
Zhou, L., Mehta, A., Schulz, E., McWilliams, B., Cho, K., Sohn, Y., Microstructure, precipitates and hardness of selectively laser melted AlSi10Mg alloy before and after heat treatment. Mater. Char., 2018, 10.1016/j.matchar.2018.04.022.
Li, Z., Zhang, D.Z., Dong, P., Kucukkoc, I., A lightweight and support-free design method for selective laser melting. Int. J. Adv. Manuf. Technol. 90 (2017), 2943–2953, 10.1007/s00170-016-9509-0.
Qiu, C., Yue, S., Adkins, N.J.E., Ward, M., Hassanin, H., Lee, P.D., Withers, P.J., Attallah, M.M., Influence of processing conditions on strut structure and compressive properties of cellular lattice structures fabricated by selective laser melting. Mater. Sci. Eng. A 628 (2015), 188–197, 10.1016/j.msea.2015.01.031.
Thijs, L., Kempen, K., Kruth, J.-P., Van Humbeeck, J., Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder. Acta Mater. 61 (2013), 1809–1819, 10.1016/j.actamat.2012.11.052.
Tang, M., Pistorius, P.C., Anisotropic mechanical behavior of AlSi10Mg parts produced by selective laser melting. JOM 69 (2017), 516–522, 10.1007/s11837-016-2230-5.
Aboulkhair, N.T., Maskery, I., Tuck, C., Ashcroft, I., Everitt, N.M., Improving the fatigue behaviour of a selectively laser melted aluminium alloy: influence of heat treatment and surface quality. Mater. Des. 104 (2016), 174–182, 10.1016/j.matdes.2016.05.041.
Suryawanshi, J., Prashanth, K.G., Scudino, S., Eckert, J., Prakash, O., Ramamurty, U., Simultaneous enhancements of strength and toughness in an Al-12Si alloy synthesized using selective laser melting. Acta Mater. 115 (2016), 285–294, 10.1016/j.actamat.2016.06.009.
Prashanth, K.G., Scudino, S., Klauss, H.J., Surreddi, K.B., Löber, L., Wang, Z., Chaubey, A.K., Kühn, U., Eckert, J., Microstructure and mechanical properties of Al–12Si produced by selective laser melting: effect of heat treatment. Mater. Sci. Eng. A 590 (2014), 153–160, 10.1016/j.msea.2013.10.023.
Rosenthal, I., Stern, A., Frage, N., Strain rate sensitivity and fracture mechanism of AlSi10Mg parts produced by Selective Laser Melting. Mater. Sci. Eng. A 682 (2017), 509–517, 10.1016/j.msea.2016.11.070.
Takata, N., Kodaira, H., Sekizawa, K., Suzuki, A., Kobashi, M., Change in microstructure of selectively laser melted AlSi10Mg alloy with heat treatments. Mater. Sci. Eng. A 704 (2017), 218–228, 10.1016/j.msea.2017.08.029.
Siddique, S., Imran, M., Walther, F., Very high cycle fatigue and fatigue crack propagation behavior of selective laser melted AlSi12 alloy. Int. J. Fatigue 94 (2017), 246–254, 10.1016/j.ijfatigue.2016.06.003.
Rao, H., Giet, S., Yang, K., Wu, X., Davies, C.H.J., The influence of processing parameters on aluminium alloy A357 manufactured by Selective Laser Melting. Mater. Des. 109 (2016), 334–346, 10.1016/j.matdes.2016.07.009.
Kim, D.-K., Woo, W., Hwang, J.-H., An, K., Choi, S.-H., Stress partitioning behavior of an AlSi10Mg alloy produced by selective laser melting during tensile deformation using in situ neutron diffraction. J. Alloy. Comp. 686 (2016), 281–286, 10.1016/j.jallcom.2016.06.011.
Wei, P., Wei, Z., Chen, Z., Du, J., He, Y., Li, J., Zhou, Y., The AlSi10Mg samples produced by selective laser melting: single track, densification, microstructure and mechanical behavior. Appl. Surf. Sci. 408 (2017), 38–50, 10.1016/j.apsusc.2017.02.215.
Li, W., Li, S., Liu, J., Zhang, A., Zhou, Y., Wei, Q., Yan, C., Shi, Y., Effect of heat treatment on AlSi10Mg alloy fabricated by selective laser melting: microstructure evolution, mechanical properties and fracture mechanism. Mater. Sci. Eng. A 663 (2016), 116–125, 10.1016/j.msea.2016.03.088.
Pfaff, A., Jäcklein, M., Hoschke, K., Wickert, M., Designed materials by additive manufacturing—impact of exposure strategies and parameters on material characteristics of AlSi10Mg processed by laser beam melting. Metals, 8, 2018, 491, 10.3390/met8070491.
Aboulkhair, N.T., Maskery, I., Tuck, C., Ashcroft, I., Everitt, N.M., The microstructure and mechanical properties of selectively laser melted AlSi10Mg: the effect of a conventional T6-like heat treatment. Mater. Sci. Eng. A 667 (2016), 139–146, 10.1016/j.msea.2016.04.092.
Purcek, G., Saray, O., Kul, O., Microstructural evolution and mechanical properties of severely deformed Al-12Si casting alloy by equal-channel angular extrusion. Met. Mater. Int. 16 (2010), 145–154, 10.1007/s12540-010-0145-1.
Ye, H., An overview of the development of Al-Si-alloy based material for engine applications. J. Mater. Eng. Perform. 12 (2003), 288–297, 10.1361/105994903770343132.
Broek, D., The role of inclusions in ductile fracture and fracture toughness. Eng. Fract. Mech. 5 (1973), 55–66, 10.1016/0013-7944(73)90007-6.
Rosenthal, D., Mathematical theory of heat distribution during welding and cutting. Weld. J. 20 (1941), 220–234.
Mertens, A., Dedry, O., Reuter, D., Rigo, O., Lecomte-Beckers, J., Thermal treatments of AlSi10Mg processed by laser beam melting. Proc. 26th Int. Solid Free, 2015, Fabr. Symp., Austin, 1007–1016.
ASTM, E., 111-04 Standard Test Method for Young's Modulus, Tangent Modulus, and Chord Modulus. 2004.
NF EN 10002-1 Metallic Materials - Tensile Testing - Part 1 : Method of Test at Ambient Temperature, 2001.
Matyja, H., The effect of cooling rate on the dendrite spacing in splat-cooled aluminium alloys. J. Inst. Met. 96 (1968), 30–32.
Tang, M., Pistorius, P.C., Narra, S., Beuth, J.L., Rapid solidification: selective laser melting of AlSi10Mg. JOM 68 (2016), 960–966, 10.1007/s11837-015-1763-3.
Yang, K.V., Rometsch, P., Davies, C.H.J., Huang, A., Wu, X., Effect of heat treatment on the microstructure and anisotropy in mechanical properties of A357 alloy produced by selective laser melting. Mater. Des. 154 (2018), 275–290, 10.1016/j.matdes.2018.05.026.
Chen, B., Moon, S.K., Yao, X., Bi, G., Shen, J., Umeda, J., Kondoh, K., Strength and strain hardening of a selective laser melted AlSi10Mg alloy. Scripta Mater. 141 (2017), 45–49, 10.1016/j.scriptamat.2017.07.025.
Tradowsky, U., White, J., Ward, R.M., Read, N., Reimers, W., Attallah, M.M., Selective laser melting of AlSi10Mg: influence of post-processing on the microstructural and tensile properties development. Mater. Des. 105 (2016), 212–222, 10.1016/j.matdes.2016.05.066.
Read, N., Wang, W., Essa, K., Attallah, M.M., Selective laser melting of AlSi10Mg alloy: process optimisation and mechanical properties development. Mater. Des. 65 (2015), 417–424, 10.1016/j.matdes.2014.09.044.
Lee, C.S., Chandel, R.S., Seow, H.P., Effect of welding parameters on the size of heat affected zone of submerged arc welding. Mater. Manuf. Process. 15 (2000), 649–666, 10.1080/10426910008913011.
Acharya, R., Sharon, J.A., Staroselsky, A., Prediction of microstructure in laser powder bed fusion process. Acta Mater. 124 (2017), 360–371, 10.1016/j.actamat.2016.11.018.
Material Data Sheet - EOS Aluminium AlSi10Mg, 2014.