Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechan...Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechanism that combines ex situ TiB_(2) and in situ Al_(3)Ti for controlling the grain structure of additively manufactured AlCuMgTi-TiB_(2) composites.We conducted thermodynamic calculations and phase-field simulations to elucidate the duplex nucleation-based grain structure control.The Al_(3)Ti-coated TiB_(2) inoculant system formed via duplex nucleation during solidification enabled the formation of a ho-mogeneous ultrafine equiaxed microstructure in both the as-fabricated and heat-treated states.Different from the AlCuMgTi alloy,the TiB_(2)-reinforced AlCuMgTi composites produced via laser powder bed fusion were amenable to the simultaneous enhancement of strength and ductility.The proposed alloy design approach and duplex nucleation mechanism can guide the tailoring of the microstructure and mechanical properties of additively manufactured aluminum parts.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52275331 and 52205358)the China Postdoctoral Science Foundation(No.2021M701293)+4 种基金the State Key Laboratory of Powder Metallurgy(Central South University,Changsha,China)the State Key Laboratory of Advanced Welding and Joining(Harbin Institute of Technology,Harbin,China)the Key-Area Research and Development Program of Guangdong Province(No.2020B090923001)the Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(No.HZQB-KCZYB-2020030)the Academic Frontier Youth Team(No.2018QYTD04)at the Huazhong University of Science and Technology.
文摘Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechanism that combines ex situ TiB_(2) and in situ Al_(3)Ti for controlling the grain structure of additively manufactured AlCuMgTi-TiB_(2) composites.We conducted thermodynamic calculations and phase-field simulations to elucidate the duplex nucleation-based grain structure control.The Al_(3)Ti-coated TiB_(2) inoculant system formed via duplex nucleation during solidification enabled the formation of a ho-mogeneous ultrafine equiaxed microstructure in both the as-fabricated and heat-treated states.Different from the AlCuMgTi alloy,the TiB_(2)-reinforced AlCuMgTi composites produced via laser powder bed fusion were amenable to the simultaneous enhancement of strength and ductility.The proposed alloy design approach and duplex nucleation mechanism can guide the tailoring of the microstructure and mechanical properties of additively manufactured aluminum parts.
