{"id":6423,"date":"2026-09-04T14:14:44","date_gmt":"2026-09-04T19:14:44","guid":{"rendered":"https:\/\/cqfa.quebec\/?p=6423"},"modified":"2026-09-04T14:16:50","modified_gmt":"2026-09-04T19:16:50","slug":"microstructural-evolution-defect-mitigation-and-precipitation-behavior-in-aa6061-via-laser-powder-bed-fusion-with-high-temperature-substrate-heating","status":"publish","type":"post","link":"https:\/\/cqfa.quebec\/en\/microstructural-evolution-defect-mitigation-and-precipitation-behavior-in-aa6061-via-laser-powder-bed-fusion-with-high-temperature-substrate-heating\/","title":{"rendered":"Microstructural evolution, defect mitigation, and precipitation behavior in AA6061 via laser powder bed fusion with high-temperature substrate heating"},"content":{"rendered":"<p><em>Karna, S.; Al-Aridi, R.; Morrall, D.; Masse, J.P.; Sun, C.; Zhang, T.; J. Gross, A.; Hosseinzadeh, H.; Martin, \u00c9.; Krentz, T.; Hitchcock, D.; Yuan, L. (2026). Microstructural evolution, defect mitigation, and precipitation behavior in AA6061 via laser powder bed fusion with high-temperature substrate heating. Materials Science and Engineering, vol. 970, 2026, 150474.<\/em><\/p>\n<p>&nbsp;<\/p>\n<p>Defects, particularly solidification cracking, remain persistent challenges in the laser powder bed fusion (LPBF) processing of AA6061 aluminum alloy. This study systematically investigates defect mitigation, microstructural evolution, and mechanical properties associated with high-temperature substrate preheating at 500\u202f\u00b0C. Comprehensive microstructural analyses, including characterization of defects, grain structures, and precipitation behavior, were performed on samples in both as-built and T6 heat-treated states. Elevated preheating substantially reduced solidification cracking across a wide processing window, while demonstrating decreased crack sensitivity to laser parameters. Columnar cracks along the build direction were observed despite substrate preheating. Lack-of-fusion and keyhole porosity were effectively eliminated, though gas-induced microporosity persisted at higher powers. In-depth characterization of two distinct laser power and speed conditions confirmed the formation of micron-sized, non-coherent Mg<sub>2<\/sub>Si precipitates under heated substrate conditions, alongside \u03b1-AlFeCrMnSi intermetallic phases indicative of in-situ thermal effects during fabrication. Subsequent T6 heat treatment revealed the formation of fine, coherent needle-shaped \u03b2\u2033 strengthening precipitates. Despite substantial differences in processing parameters, comparable mechanical properties were measured in the as-built samples (\u223c52\u202fMPa yield strength, \u223c130\u202fMPa tensile strength), primarily due to reduced strain hardening effects and consistent precipitation characteristics. Meanwhile, the T6 heat treatment led to significant improvement in properties, enhancing yield strength by over 400%, aligning closely with the performance of conventional wrought AA6061-T6. These findings underscore that high-temperature substrate preheating offers an effective means to suppress cracks, control precipitation, and enhance mechanical performance in LPBF-processed AA6061.<\/p>\n<p>&nbsp;<\/p>\n<p class=\"link-btn-style btn-yellow\"><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0921509326007549\" target=\"_blank\" rel=\"noopener\">Read the publication<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Karna, S.; Al-Aridi, R.; Morrall, D.; Masse, J.P.; Sun, C.; Zhang, T.; J. Gross, A.; Hosseinzadeh, H.; Martin, \u00c9.; Krentz, T.; Hitchcock, D.; Yuan, L. (2026). Microstructural evolution, defect mitigation, [&hellip;]<\/p>\n","protected":false},"author":80,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":""},"categories":[43],"tags":[],"class_list":["post-6423","post","type-post","status-publish","format-standard","hentry","category-publications-academiques-quebecoises"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Microstructural evolution, defect mitigation, and precipitation behavior in AA6061 via laser powder bed fusion with high-temperature substrate heating - CQFA - Carrefour qu\u00e9b\u00e9cois de la fabrication additive<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/cqfa.quebec\/en\/microstructural-evolution-defect-mitigation-and-precipitation-behavior-in-aa6061-via-laser-powder-bed-fusion-with-high-temperature-substrate-heating\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Microstructural evolution, defect mitigation, and precipitation behavior in AA6061 via laser powder bed fusion with high-temperature substrate heating - CQFA - Carrefour qu\u00e9b\u00e9cois de la fabrication additive\" \/>\n<meta property=\"og:description\" content=\"Karna, S.; Al-Aridi, R.; Morrall, D.; Masse, J.P.; Sun, C.; Zhang, T.; J. 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