In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperature...In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperatures of 523?823 K and strain rates of 0.005?10 s?1 on a Gleeble?1500 thermo-simulation machine. The influence rule of processing parameters (strain, strain rate and temperature) on flow stress of pure aluminum was investigated. Nine analysis factors consisting of material parameters and according weights were optimized. Then, the constitutive equations of multilevel series rules, multilevel parallel rules and multilevel series ¶llel rules were established. The correlation coefficients (R) are 0.992, 0.988 and 0.990, respectively, and the average absolute relative errors (AAREs) are 6.77%, 8.70% and 7.63%, respectively, which proves that the constitutive equations of multilevel series rules can predict the flow stress of pure aluminum with good correlation and precision.展开更多
A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?G...A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?Ge filler metals drops from 592 to 519 °C as the content of Ge increases from 0 to 30% (mass fraction). As the content of Ge increases, bright eutectic Ge forms. However, as the Ge content exceeds 20%, the aggregation growth of the eutectic structure tends to happen and coarsened primary Si?Ge particle forms, which is detrimental to the properties of alloys. The Al?10.8Si?10Ge filler metal has good processability and wettability with the base metal Al. When this filler metal is used to braze 1060 aluminum, the complete joint can be achieved. Furthermore, the shear strength test results show that the fracture of brazed joint with Al?10.8Si?10Ge filler metal occurs in the base metal.展开更多
9. 6 mm thick 1060-H24 aluminum alloy plates were friction stir welded and the influencing factors on groove and tunnel defects were examined. Results show that the welding speed range for achieving a groove-free join...9. 6 mm thick 1060-H24 aluminum alloy plates were friction stir welded and the influencing factors on groove and tunnel defects were examined. Results show that the welding speed range for achieving a groove-free joint is enlarged with increasing the rotating speed. The tunnel size decreases with decreasing the welding speed under the same rotating speed. Excessive or insufficient shoulder plunge depth will cause defective joints. At a relatively low rotating speed and high welding speed, the tool having a larger shoulder diameter has a larger range of processing parameters to obtain a groove-free joint. Moreover, the tensile fracture behaviors of the defective and defect-free samples are different.展开更多
Ultrafine-grained(UFG)AA1060 sheets were fabricated via five-cycle accumulative roll bonding(ARB)and subsequent three-pass cold rolling(298 K),or cryorolling(83 K and 173 K).Microstructures of the aluminum samples wer...Ultrafine-grained(UFG)AA1060 sheets were fabricated via five-cycle accumulative roll bonding(ARB)and subsequent three-pass cold rolling(298 K),or cryorolling(83 K and 173 K).Microstructures of the aluminum samples were examined via transmission electron microscopy,and their mechanical properties were measured via tensile and microhardness testing.Results indicate that ultrafine grains in ARB-processed sheets were further refined by subsequent rolling,and the grain size became finer with reducing rolling temperature.The mean grain size of 666 nm in the sheets subjected to ARB was refined to 346 or 266 nm,respectively,via subsequent cold rolling or cryorolling(83 K).Subsequent cryorolling resulted in ultrafine-grained sheets of higher strength and ductility than those of the sheets subjected to cold rolling.展开更多
基金Project(51275414)supported by the National Natural Science Foundation of ChinaProject(2015JM5204)supported by the Natural Science Foundation of Shaanxi Province,China+1 种基金Project(Z2015064)supported by the Graduate Starting Seed Fund of the Northwestern Polytechnical University,ChinaProject(130-QP-2015)supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China
文摘In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperatures of 523?823 K and strain rates of 0.005?10 s?1 on a Gleeble?1500 thermo-simulation machine. The influence rule of processing parameters (strain, strain rate and temperature) on flow stress of pure aluminum was investigated. Nine analysis factors consisting of material parameters and according weights were optimized. Then, the constitutive equations of multilevel series rules, multilevel parallel rules and multilevel series ¶llel rules were established. The correlation coefficients (R) are 0.992, 0.988 and 0.990, respectively, and the average absolute relative errors (AAREs) are 6.77%, 8.70% and 7.63%, respectively, which proves that the constitutive equations of multilevel series rules can predict the flow stress of pure aluminum with good correlation and precision.
基金Project(2010A080402014)supported by the Guangdong Provincial Science and Technology Foundation,China
文摘A series of Al?Si?Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al?Si?Ge filler metals drops from 592 to 519 °C as the content of Ge increases from 0 to 30% (mass fraction). As the content of Ge increases, bright eutectic Ge forms. However, as the Ge content exceeds 20%, the aggregation growth of the eutectic structure tends to happen and coarsened primary Si?Ge particle forms, which is detrimental to the properties of alloys. The Al?10.8Si?10Ge filler metal has good processability and wettability with the base metal Al. When this filler metal is used to braze 1060 aluminum, the complete joint can be achieved. Furthermore, the shear strength test results show that the fracture of brazed joint with Al?10.8Si?10Ge filler metal occurs in the base metal.
基金The work is supported by the National Natural Science Foundation of China （51005180） and the Research Fund of the State Key Laboratory of Solidification Processing （69-QP-2011 ）.
文摘9. 6 mm thick 1060-H24 aluminum alloy plates were friction stir welded and the influencing factors on groove and tunnel defects were examined. Results show that the welding speed range for achieving a groove-free joint is enlarged with increasing the rotating speed. The tunnel size decreases with decreasing the welding speed under the same rotating speed. Excessive or insufficient shoulder plunge depth will cause defective joints. At a relatively low rotating speed and high welding speed, the tool having a larger shoulder diameter has a larger range of processing parameters to obtain a groove-free joint. Moreover, the tensile fracture behaviors of the defective and defect-free samples are different.
基金financial supports from the National Key Research and Development Program of China (No. 2019YFB2006500)the National Natural Science Foundation of China (No. 51674303)+2 种基金the Huxiang High-level Talent Gathering Project of Hunan Province, China (No. 2018RS3015)the Innovation Driven Program of Central South University, China (No. 2019CX006)the Research Fund of the Key Laboratory of High Performance Complex Manufacturing at Central South University, China。
文摘Ultrafine-grained(UFG)AA1060 sheets were fabricated via five-cycle accumulative roll bonding(ARB)and subsequent three-pass cold rolling(298 K),or cryorolling(83 K and 173 K).Microstructures of the aluminum samples were examined via transmission electron microscopy,and their mechanical properties were measured via tensile and microhardness testing.Results indicate that ultrafine grains in ARB-processed sheets were further refined by subsequent rolling,and the grain size became finer with reducing rolling temperature.The mean grain size of 666 nm in the sheets subjected to ARB was refined to 346 or 266 nm,respectively,via subsequent cold rolling or cryorolling(83 K).Subsequent cryorolling resulted in ultrafine-grained sheets of higher strength and ductility than those of the sheets subjected to cold rolling.
