Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolli...Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolling and thermo-mechanical heat treatment(T8)with pre-stretching deformation between solution and aging treatment were adopted in this study.Their effects on hardness,mechanical properties and microstructure were analyzed and compared to the conventional heat treatment(T6).The results show that cold rolling increases the hardness and strengths,which further increase with T8 treatment.The ultimate tensile strength(UTS)of 513 MPa and yield stress(YS)of 413 MPa can be obtained in the inter-layer cold-rolled sample with T8 treatment,which is much higher than that in the as-deposited samples.The cold-rolled samples show higher elongation than that of as-deposited ones due to significant elimination of porosity in cold rolling;while both the T6 and T8 treatments decrease the elongation.The cold rolling and pre-stretching deformation both contribute to the formation of dense and dispersive precipitatedθ′phases,which inhibits the dislocation movement and enhances the strengths;as a result,T8 treatment shows better strengthening effect than the T6 treatment.The strengthening mechanism was analyzed and it was mainly related to work hardening and precipitation strengthening.展开更多
The influence of the low voltage pulsed magnetic field(LVPMF)on the microstructure transition of K4169 superalloy was investigated.The gradient microstructure of K4169 superalloy composed of columnar grains,coarse gra...The influence of the low voltage pulsed magnetic field(LVPMF)on the microstructure transition of K4169 superalloy was investigated.The gradient microstructure of K4169 superalloy composed of columnar grains,coarse grains,and fine grains was prepared through the combined method of LVPMF with directional solidification,which provided a new approach for the preparation of superalloy with gradient microstructure.The distribution of the Lorentz force and flow field under LVPMF effect was simulated,and therefore the microstructure transition mechanism was revealed.Results show that the microstructure transition should be attributed to the coupling effects of the Lorentz force and forced convection.展开更多
基金Project(ZZYJKT2024-08)supported by the State Key Laboratory of Precision Manufacturing for Extreme Service Performance,ChinaProject(2022JB11GX004)supported by Selection of the best Candidates to Undertake Key Research Projects by Dalian City,ChinaProject(201806835007)supported by China Scholarship Council。
文摘Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolling and thermo-mechanical heat treatment(T8)with pre-stretching deformation between solution and aging treatment were adopted in this study.Their effects on hardness,mechanical properties and microstructure were analyzed and compared to the conventional heat treatment(T6).The results show that cold rolling increases the hardness and strengths,which further increase with T8 treatment.The ultimate tensile strength(UTS)of 513 MPa and yield stress(YS)of 413 MPa can be obtained in the inter-layer cold-rolled sample with T8 treatment,which is much higher than that in the as-deposited samples.The cold-rolled samples show higher elongation than that of as-deposited ones due to significant elimination of porosity in cold rolling;while both the T6 and T8 treatments decrease the elongation.The cold rolling and pre-stretching deformation both contribute to the formation of dense and dispersive precipitatedθ′phases,which inhibits the dislocation movement and enhances the strengths;as a result,T8 treatment shows better strengthening effect than the T6 treatment.The strengthening mechanism was analyzed and it was mainly related to work hardening and precipitation strengthening.
基金National Key Research and Development Program of China(2018YFA0702900)National Science and Technology Major Project(J2019-VII-0002-0142)National Natural Science Foundation of China(51831007)。
文摘The influence of the low voltage pulsed magnetic field(LVPMF)on the microstructure transition of K4169 superalloy was investigated.The gradient microstructure of K4169 superalloy composed of columnar grains,coarse grains,and fine grains was prepared through the combined method of LVPMF with directional solidification,which provided a new approach for the preparation of superalloy with gradient microstructure.The distribution of the Lorentz force and flow field under LVPMF effect was simulated,and therefore the microstructure transition mechanism was revealed.Results show that the microstructure transition should be attributed to the coupling effects of the Lorentz force and forced convection.
