摘要
Rapid cooling and solidification during laser additive manufacturing(LAM)can produce ultra-fine microstructure with higher strength.However,the non-uniform cell/grain structure can easily result in early stress concentration and fracture during deformation,which remains a major challenge for the LAM field.Using Al-12Si as the model alloy,we employed the external static magnetic field(SMF)to modulate the laser powder bed fusion process(L-PBF),demonstrating a uniform microstructure with a refined cell structure.The mechanical properties show that the SMF can produce a combination of high tensile strength of 451.4±0.5 MPa and large uniform elongation of 10.4%±0.79%,which are superior to those of previously-reported Al-Si alloys with post-treatment or element alloying.The mechanism analysis based on multi-scale simulation reveals the determining role of SMF in rapid solidification,and this method is applicable to the microstructure control of other metallic materials during LAM.
基金
the National Key Research and Development Program of China(No.2019YFA0705300,2021YFB3702502)
the National Natural Science Foundation of China(Nos.52001191,52127807,52271035)
Natural Science Foundation of Shanghai(No.23ZR1421500)
SPMI Project from Shanghai Academy of Spaceflight Technology(No.SPMI2022-06)
Independent Research Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy
Shanghai University(No.SKLASS 2022-Z10)
the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
