Crack-free and high-strength AA2024 alloy obtained by additive manufacturing with controlled columnar-equiaxed-transition
作者机构：School of Mechanical EngineeringNanjing University of Science and TechnologyNanjing 210094China
出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)
年 卷 期：2023年第156卷第25期
页 面：183-196页
核心收录：
学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学]
基 金：supported by the National Natural Science Foundation of China(Nos.52175330 and 51805267) the Frontier Leading Technology Basic Research Project of Jiangsu(No.BK20202007) the Fundamental Research Funds for the Central Universities(No.30921011202)
主 题：Laser powder bed fusion Aluminum alloy Solidification parameters Columnar-equiaxed-transition Hot cracking Grain refinement
摘 要：Laser powder bed fusion(LPBF)of high-strength Al alloys is challenging due to the formation of both hot and cold *** the present work,highly dense and crack-free AA2024 samples could be additively manufactured via inoculation treatment of Zr-based metallic glass(MG)*** columnar grains in the LPBF-fabricated AA2024 alloy were significantly refined and almost completely transformed to the equiaxed grains with a bimodal grain size distribution consisting of ultrafine grains with a size smaller than 1μm and relatively coarser *** grain refinement can be associated with the formation of Al3Zr particles,serving as the heterogeneous nucleation sites for theα-Al *** routes for columnar-equiaxed-transition(CET)have been revealed by tailoring the concentration of nucleation particles and solidification *** occurs both at the melt pool boundary due to the sufficiently high concentration of Al3Zr particles and at the topmost of the melt pool due to the heterogeneous nucleation driven by constitutional *** these two regions,columnar grains epitaxially grow with orientations determined by the thermal *** as-built Zr-based MG inoculated AA2024 specimens are robust in healing hot cracks due to a more tortuous propagation path of cracks for equiaxed *** as-fabricated AA2024/5%MG specimens exhibit a high ultimate tensile strength of 531 MPa due to crack elimination and grain refinement,surpassing most of the reported values for the LPBF-fabricated AA2024 alloy inoculated with other inoculated *** present work could provide a novel inoculation agent to fabricate high-strength Al alloys and the CET can be used to precisely control the grain morphology.
维普期刊数据库