Interface stability homogeneity control remains a challenging problem in large-scale laser-melting-deposited ti-tanium(LLMDT)alloy components for aerospace applications.In this study,the homogeneity of the interface s...Interface stability homogeneity control remains a challenging problem in large-scale laser-melting-deposited ti-tanium(LLMDT)alloy components for aerospace applications.In this study,the homogeneity of the interface stability of LLMDT components after post heat treatment was investigated.Recrystallized grains nucleated and grew in the equiaxed and columnar grain regions in the LLMDT part,whereas they did not form in the interface re-gion because the recrystallization driving force in the interface region was lower than that in the LLMDT part.The microstructures of the LLMDT components showed coarsened𝛼lamellae,and their width varied from 1.65μm to 2.18μm.The𝛼lamellae did not completely coarsen during post heat treatment(950°C/1 h/air cooling+550°C/4 h/air cooling)because of the low coarsening driving force.For the LLMDT components,the ultimate tensile strength(UTS)and yield strength(YS)were slightly different in different regions owing to the slight difference in the width of the𝛼lamellae.The elongation(EL)of the LLMDT components exhibited no difference,and there was nearly zero anisotropic ductility.The highest fluctuation ratios of the UTS,YS,and EL were 3.11%,3.8%,and 7.18%,respectively.The tensile properties of the LLMDT components showed no difference in the different regions,indicating interface stability homogeneity.展开更多
Isothermal forging stands as an effective technology for the production of large-scale titanium alloy multi-rib components.However,challenges have persisted,including die underfilling and strain concentration due to t...Isothermal forging stands as an effective technology for the production of large-scale titanium alloy multi-rib components.However,challenges have persisted,including die underfilling and strain concentration due to the complex material flow and heterogeneous deformation within the forging die cavity.While approaches centered on optimized billet designs have mitigated these challenges,uncertainties in process parameters continue to introduce unacceptable variations in forming accuracy and stability.To tackle this issue,this study introduced a multi-objective robust optimization approach for billet design,accounting for the multi-rib eigenstructure and potential uncertainties.The approach includes finite element(FE)modeling for analyzing the die-filling and strain inhomogeneity within the multi-rib eigenstructure.Furthermore,it integrated image acquisition perception and feed back technologies(IAPF)for real-time monitoring of material flow and filling sequences within die rib-grooves,validating the accuracy of the FE modeling.By incorporating dimensional parameters of the billet and uncertainty factors,including friction,draft angle,forming temperature,speed,and deviations in billet and die,quantitative analyses on the rib-groove filling and strain inhomogeneity with fluctuation were conducted.Subsequently,a dual-response surface model was developed for statistical analysis of the cavity filling and strain homogeneity.Finally,the robust optimization was processed using a non-dominated sorting genetic algorithm II(NSGA-II)and validated using the IAPF technologies.The proposed approach enables robust design enhancements for rib-groove filling and strain homogeneity in titanium alloy multi-rib components.展开更多
基金supported by the National Key Research and Devel-opment Program of China(Grant No.2022YFB4602205).
文摘Interface stability homogeneity control remains a challenging problem in large-scale laser-melting-deposited ti-tanium(LLMDT)alloy components for aerospace applications.In this study,the homogeneity of the interface stability of LLMDT components after post heat treatment was investigated.Recrystallized grains nucleated and grew in the equiaxed and columnar grain regions in the LLMDT part,whereas they did not form in the interface re-gion because the recrystallization driving force in the interface region was lower than that in the LLMDT part.The microstructures of the LLMDT components showed coarsened𝛼lamellae,and their width varied from 1.65μm to 2.18μm.The𝛼lamellae did not completely coarsen during post heat treatment(950°C/1 h/air cooling+550°C/4 h/air cooling)because of the low coarsening driving force.For the LLMDT components,the ultimate tensile strength(UTS)and yield strength(YS)were slightly different in different regions owing to the slight difference in the width of the𝛼lamellae.The elongation(EL)of the LLMDT components exhibited no difference,and there was nearly zero anisotropic ductility.The highest fluctuation ratios of the UTS,YS,and EL were 3.11%,3.8%,and 7.18%,respectively.The tensile properties of the LLMDT components showed no difference in the different regions,indicating interface stability homogeneity.
基金Supported by National Natural Science Foundation of China(Grant No.52005241)Jiangxi Provincial Natural Science Foundation(Grant Nos.20232BAB204050,20224BAB204045)China Scholarship Council(Grant No.202208360107).
文摘Isothermal forging stands as an effective technology for the production of large-scale titanium alloy multi-rib components.However,challenges have persisted,including die underfilling and strain concentration due to the complex material flow and heterogeneous deformation within the forging die cavity.While approaches centered on optimized billet designs have mitigated these challenges,uncertainties in process parameters continue to introduce unacceptable variations in forming accuracy and stability.To tackle this issue,this study introduced a multi-objective robust optimization approach for billet design,accounting for the multi-rib eigenstructure and potential uncertainties.The approach includes finite element(FE)modeling for analyzing the die-filling and strain inhomogeneity within the multi-rib eigenstructure.Furthermore,it integrated image acquisition perception and feed back technologies(IAPF)for real-time monitoring of material flow and filling sequences within die rib-grooves,validating the accuracy of the FE modeling.By incorporating dimensional parameters of the billet and uncertainty factors,including friction,draft angle,forming temperature,speed,and deviations in billet and die,quantitative analyses on the rib-groove filling and strain inhomogeneity with fluctuation were conducted.Subsequently,a dual-response surface model was developed for statistical analysis of the cavity filling and strain homogeneity.Finally,the robust optimization was processed using a non-dominated sorting genetic algorithm II(NSGA-II)and validated using the IAPF technologies.The proposed approach enables robust design enhancements for rib-groove filling and strain homogeneity in titanium alloy multi-rib components.
