Three-layer composite ingot of 4045/3004/4045 aluminum alloys was prepared by direct-chill semi-continuous casting process,the temperature field distribution near the composite interface,macro-morphology,microstructur...
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Three-layer composite ingot of 4045/3004/4045 aluminum alloys was prepared by direct-chill semi-continuous casting process,the temperature field distribution near the composite interface,macro-morphology,microstructure and composition distribution of the composite interface were *** results show that semi-solid layer with a certain thickness forms near the interface due to the effect of cooling plate,which ensures successful implementation of casting the composite *** different aluminum alloys are well bonded *** mechanical properties of composite interface were measured,the tensile and shearing strengths of composite interface are 105 and 88 MPa,respectively,which proves that the composite interface is a kind of metallurgical bonding.
Low frequency electromagnetic casting （LFEC） process with the application of an induction coil outside the conventional direct chill （DC） casting mould was used to prepare the flat ingot of 2524 alloy and the effe...
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Low frequency electromagnetic casting （LFEC） process with the application of an induction coil outside the conventional direct chill （DC） casting mould was used to prepare the flat ingot of 2524 alloy and the effect of electromagnetic field on the microstructure and macrosegregation of this alloy was systematically studied. The results show that the fiat ingot prepared by the LFEC process has a finer and more uniform as-cast microstructure and the grain morphology is transformed from dendrite and rosette-like to equiaxed structure. The LFEC process also shows a significant effect on macrosegregation, and with the application of electromagnetic field during casting process, the segregation in the centre of the ingot is obviously reduced. The mechanism of these effects was also discussed.
Effects of additions minor contents of 0.03%Sc and 0.12%Zr and solution treatment on microstructure and mechanical properties of Al-9.0Zn-2.8Mg-2.5Cu alloy were studied by metallographic microscopy, differential therm...
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Effects of additions minor contents of 0.03%Sc and 0.12%Zr and solution treatment on microstructure and mechanical properties of Al-9.0Zn-2.8Mg-2.5Cu alloy were studied by metallographic microscopy, differential thermal analysis （DSC） and transmission electron microscopy （TEM）, in order to obtain high-performance Al alloys. The minor additions of Sc （less than 0.1%） were carried out. The results show that with the additions of 0.03% Sc and 0.12% Zr, the petaloid Al3（Sc,Zr） precipitated phases occur in Al-9.0Zn-2.8Mg-2.5Cu alloy, and Al3（Sc,Zr） particles obviously hinder the recrystallization of Al-9.0Zn-2.8Mg-2.5Cu alloy during homogenizing and extruding processes due to their strong pinning effect on dislocation. Multi-stage solution is better than single solution, for it can avoid recrystallization of Al-9.0Zn-2.8Mg-2.5Cu alloy with the minor contents of Sc （less than 0.1%）. The proper solution treatment is （420 °C, 3 h）＋（465 °C, 2 h） under which Al-9.0Zn-2.8Mg-2.5Cu-0.12Zr-0.03Sc alloy obtains a tensile strength of 777.29 MPa and a elongation of 11.84%.
The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinemen...
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The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.
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