High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking...High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking suppression mechanism and phase formation in these composites are not clarified.In this work,microstructure evolution and mechanical performance of the LPBF-fabricated Ti/Ce co-modified 2195 are investigated to reveal their cracking suppression and strengthening mechanisms.The results show that apparent grain refinement of the composites is ascribed to high supercooling from rapid formation of constitutional supercooling zone in front of solid–liquid interfaces by high-Q-value Ti solute,and heterogeneous nucleation of in situ formed Al3Ti and Al11Ce3precipitates.Their synergistic interactions promote formation of fine equiaxed grains and thus inhibit crack initiation.The composites exhibit high microhardness of 100±5HV0.2,nano-hardness of 1.6±0.1 GPa and elastic modulus of 97±3 GPa,where the elastic modulus increases by 27%and 31%compared to those of LPBF-processed and conventionally manufactured 2195 alloys,respectively.A tensile strength of 336 MPa and an elongation of 3%are obtained from in-situ synchrotron X-ray diffraction measurement.The improved properties are derived from grain refinement and Orowan strengthening.Based on the optimal processing parameter and composition,a bracket component filled with lattice structures is designed and manufactured with good manufacturing quality and processing accuracy.展开更多
The impact of cryorolling(CR)and room temperature rolling(RTR)followed by artificial aging on the corrosion characteristics of 2195 Al−Li alloy(AA2195)was studied.Transmission electron microscope,scanning electron mic...The impact of cryorolling(CR)and room temperature rolling(RTR)followed by artificial aging on the corrosion characteristics of 2195 Al−Li alloy(AA2195)was studied.Transmission electron microscope,scanning electron microscope,optical microscope,intergranular corrosion experiment,and electrochemical experiment were used.Throughout different stages of aging treatment,the corrosion behavior of both CR and RTR samples exhibited a sequential progression of pitting corrosion,followed by intergranular corrosion,and then pitting corrosion again.The corrosion rates of both samples initially showed an increase,followed by a gradual stabilization over time.The size and density of T1 phase significantly influenced the corrosion performance of the alloy.During the peak aging and over-aging stages,the CR sample exhibited superior corrosion resistance to the RTR sample,attributed to its finer T1 phase.展开更多
Friction stir additive manufacturing(FSAM)is an innovative additive manufacturing(AM)method.The various heat treatment conditions of aluminum-lithium alloys using this method have not been widely discussed.In this stu...Friction stir additive manufacturing(FSAM)is an innovative additive manufacturing(AM)method.The various heat treatment conditions of aluminum-lithium alloys using this method have not been widely discussed.In this study,the microstructure evolution and mechanical properties of FSAM 2195 aluminum-lithium alloy in different heat treatment conditions(T3 and T8)were investigated.The results demonstrated that the heat treatment state of 2195 Al-Li alloys was minimally influenced by FSAM as the FSAM temperature exceeded the solid solution temperature.After conducting a single-pass FSAM experiment,a notable grain refinement was observed in the nugget zone(NZ)region compared to the base material(BM).The average grain size of the 2195-T3 alloy decreased from 6.1 to 2.9µm,while the proportion of high-angle grain boundaries increased from 16.5%to 43.9%.Similarly,the average grain size of the 2195-T8 alloy decreased from 8.9 to 2.8µm,with an increase in high-angle grain boundary from 37.6%to 59.2%.The tensile strength of the 2195-T3 Al-Li alloy reached 466 and 478 MPa in the NZ of single-pass and lap experiments,respectively.In comparison,the tensile strength of the 2195-T8 Al-Li alloy in the NZ could reach 452 and 481 MPa in single-pass and lap experiments,respectively.These results demonstrate the significant improvements in microstructure and mechanical properties were achieved through the FSAM process.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52205382,52225503)National Key Research and Development Program(No.2023YFB4603300)+3 种基金Key Research and Development Program of Jiangsu Province(Nos.BE2022069,BZ2024019)National Natural Science Foundation of China for Creative Research Groups(No.51921003)International Joint Laboratory of Sustainable Manufacturing,Ministry of Education and the Fundamental Research Funds for the Central Universities(NG2024014)Postgraduate Research&Practice Innovation Program of NUAA(xcxjh20230616)。
文摘High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking suppression mechanism and phase formation in these composites are not clarified.In this work,microstructure evolution and mechanical performance of the LPBF-fabricated Ti/Ce co-modified 2195 are investigated to reveal their cracking suppression and strengthening mechanisms.The results show that apparent grain refinement of the composites is ascribed to high supercooling from rapid formation of constitutional supercooling zone in front of solid–liquid interfaces by high-Q-value Ti solute,and heterogeneous nucleation of in situ formed Al3Ti and Al11Ce3precipitates.Their synergistic interactions promote formation of fine equiaxed grains and thus inhibit crack initiation.The composites exhibit high microhardness of 100±5HV0.2,nano-hardness of 1.6±0.1 GPa and elastic modulus of 97±3 GPa,where the elastic modulus increases by 27%and 31%compared to those of LPBF-processed and conventionally manufactured 2195 alloys,respectively.A tensile strength of 336 MPa and an elongation of 3%are obtained from in-situ synchrotron X-ray diffraction measurement.The improved properties are derived from grain refinement and Orowan strengthening.Based on the optimal processing parameter and composition,a bracket component filled with lattice structures is designed and manufactured with good manufacturing quality and processing accuracy.
基金supported by the High-tech Industry Technology Innovation Leading Plan of Hunan Province,China(No.2022GK4032)the State Key Laboratory of Precision Manufacturing for Extreme Service Performance at Central South University,China.
文摘The impact of cryorolling(CR)and room temperature rolling(RTR)followed by artificial aging on the corrosion characteristics of 2195 Al−Li alloy(AA2195)was studied.Transmission electron microscope,scanning electron microscope,optical microscope,intergranular corrosion experiment,and electrochemical experiment were used.Throughout different stages of aging treatment,the corrosion behavior of both CR and RTR samples exhibited a sequential progression of pitting corrosion,followed by intergranular corrosion,and then pitting corrosion again.The corrosion rates of both samples initially showed an increase,followed by a gradual stabilization over time.The size and density of T1 phase significantly influenced the corrosion performance of the alloy.During the peak aging and over-aging stages,the CR sample exhibited superior corrosion resistance to the RTR sample,attributed to its finer T1 phase.
基金Project(U22A20190)supported by International Science and Technology Cooperation under the National Natural Science Foundation of ChinaProjects(U2241248,52205379)supported by the National Natural Science Foundation of ChinaProject(BE2023026)supported by Jiangsu Provincial Key Research and Development Program and Nanjing Science and Technology Innovation Project for Overseas Scholars,China。
文摘Friction stir additive manufacturing(FSAM)is an innovative additive manufacturing(AM)method.The various heat treatment conditions of aluminum-lithium alloys using this method have not been widely discussed.In this study,the microstructure evolution and mechanical properties of FSAM 2195 aluminum-lithium alloy in different heat treatment conditions(T3 and T8)were investigated.The results demonstrated that the heat treatment state of 2195 Al-Li alloys was minimally influenced by FSAM as the FSAM temperature exceeded the solid solution temperature.After conducting a single-pass FSAM experiment,a notable grain refinement was observed in the nugget zone(NZ)region compared to the base material(BM).The average grain size of the 2195-T3 alloy decreased from 6.1 to 2.9µm,while the proportion of high-angle grain boundaries increased from 16.5%to 43.9%.Similarly,the average grain size of the 2195-T8 alloy decreased from 8.9 to 2.8µm,with an increase in high-angle grain boundary from 37.6%to 59.2%.The tensile strength of the 2195-T3 Al-Li alloy reached 466 and 478 MPa in the NZ of single-pass and lap experiments,respectively.In comparison,the tensile strength of the 2195-T8 Al-Li alloy in the NZ could reach 452 and 481 MPa in single-pass and lap experiments,respectively.These results demonstrate the significant improvements in microstructure and mechanical properties were achieved through the FSAM process.
