The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,...The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,effectively controlling the material flow to achieve a reduced loading force and near-uniformity in the isothermal plastic forming process of large-scale asymmetric magnesium alloy complex housings(LSMACHs)is challenging.This study proposes a material flow control method based on the diffluence upsetting-extrusion forming(DUEF)process by dividing different forging deformation regions,combining these with the principal stress method,and establishing an efficient and accurate design procedure.A rational preformed billet was designed successfully using this method.Subsequently,a finite element simulation was employed to analyze the multiphysics fields of the DUEF process.The results indicated that compared with the traditional closed-die forging(TCDF)process,the DUEF process could control the orderly flow of materials,achieve short-distance filling of materials,and reduce hydrostatic stress.Simultaneously,it improved the deformation uniformity by 20.3%and reduced the loading force by 22.6%.Finally,the rationality of the proposed method was validated through physical experiments.Compared with the TCDF process,the DUEF process exhibited a low loading force and uniform mechanical properties.The proposed material flow control method based on the DUEF process provides a new technological approach for the plastic formation of LSMACH and similar components.展开更多
The Caucasian-Arabian belt is part of the huge late Cenozoic Alpine-Himalayan orogenic belt formed by collision of continental plates. The belt consists of two domains： the Caucasian-Arabian Syntaxis （CAS） in the s...The Caucasian-Arabian belt is part of the huge late Cenozoic Alpine-Himalayan orogenic belt formed by collision of continental plates. The belt consists of two domains： the Caucasian-Arabian Syntaxis （CAS） in the south and the EW-striking Greater Caucasus in the north. The GAS marks a zone of the indentation of the Arabian plate into the southern East European Craton. The Greater Caucasus Range is located in the south of the Eurasian plate; it was tectonically uplifted along the Main Caucasian Fault （MCF）, which is, in turn, a part of a megafault extended over a great distance from the Kopetdag Mts. to the Tornquist- Teisseyre Trans-European Suture Zone. The Caucasus Mts. are bounded by the Black Sea from the west and by the Caspian Sea from the east. The SN-striking CAS is characterized by a large geophysical isostatic anomaly suggesting presence of mantle plume head. A 500 km long belt of late Cenozoic volcanism in the CAS extends from the eastern Anatolia to the Lesser and Greater Caucasus ranges. This belt hosts two different types of volcanic rocks： （1） plume-type intraplate basaltic plateaus and （2） suprasubductiontype calc-alkaline and shoshonite-latite volcanic rocks. As the CAS lacks signatures of subduction zones and is characterized by relatively shallow earthquakes （50 60 kin）. we suggest that the ＂supra- subduction-type＂ magmas were derived by interaction between mantle plume head and crustal material. Those hybrid melts were originated under conditions of collision-related deformation. During the late Cenozoic, the width of the CAS reduced to ca. 400 km due to tectonic ＂diffluence＂ of crustal material Drovided bv the continuing Arabia-Eurasia collision.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.52075501).
文摘The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,effectively controlling the material flow to achieve a reduced loading force and near-uniformity in the isothermal plastic forming process of large-scale asymmetric magnesium alloy complex housings(LSMACHs)is challenging.This study proposes a material flow control method based on the diffluence upsetting-extrusion forming(DUEF)process by dividing different forging deformation regions,combining these with the principal stress method,and establishing an efficient and accurate design procedure.A rational preformed billet was designed successfully using this method.Subsequently,a finite element simulation was employed to analyze the multiphysics fields of the DUEF process.The results indicated that compared with the traditional closed-die forging(TCDF)process,the DUEF process could control the orderly flow of materials,achieve short-distance filling of materials,and reduce hydrostatic stress.Simultaneously,it improved the deformation uniformity by 20.3%and reduced the loading force by 22.6%.Finally,the rationality of the proposed method was validated through physical experiments.Compared with the TCDF process,the DUEF process exhibited a low loading force and uniform mechanical properties.The proposed material flow control method based on the DUEF process provides a new technological approach for the plastic formation of LSMACH and similar components.
基金supported by a RFBR-TUBITAK grant(Project No.09-05-91220-ST-aco-leaders E.Sharkov and M.Keskin)+2 种基金Scientific Project of IGM SB RASMinistry of Education and Science(Russia)Project No 14.B25.31.0032JSPS Grant-in-Aid No.14526
文摘The Caucasian-Arabian belt is part of the huge late Cenozoic Alpine-Himalayan orogenic belt formed by collision of continental plates. The belt consists of two domains： the Caucasian-Arabian Syntaxis （CAS） in the south and the EW-striking Greater Caucasus in the north. The GAS marks a zone of the indentation of the Arabian plate into the southern East European Craton. The Greater Caucasus Range is located in the south of the Eurasian plate; it was tectonically uplifted along the Main Caucasian Fault （MCF）, which is, in turn, a part of a megafault extended over a great distance from the Kopetdag Mts. to the Tornquist- Teisseyre Trans-European Suture Zone. The Caucasus Mts. are bounded by the Black Sea from the west and by the Caspian Sea from the east. The SN-striking CAS is characterized by a large geophysical isostatic anomaly suggesting presence of mantle plume head. A 500 km long belt of late Cenozoic volcanism in the CAS extends from the eastern Anatolia to the Lesser and Greater Caucasus ranges. This belt hosts two different types of volcanic rocks： （1） plume-type intraplate basaltic plateaus and （2） suprasubductiontype calc-alkaline and shoshonite-latite volcanic rocks. As the CAS lacks signatures of subduction zones and is characterized by relatively shallow earthquakes （50 60 kin）. we suggest that the ＂supra- subduction-type＂ magmas were derived by interaction between mantle plume head and crustal material. Those hybrid melts were originated under conditions of collision-related deformation. During the late Cenozoic, the width of the CAS reduced to ca. 400 km due to tectonic ＂diffluence＂ of crustal material Drovided bv the continuing Arabia-Eurasia collision.
