F. Yang
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C. H. Wu and D. L. Sun School of Materials Science & Engineering
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Harbin Institute of Technology
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Harbin 150001
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China
金属学报(英文版)
Dimensional stability properties of hot extruded 2024 Al alloy bar in T4 and T6 aging states and dif- ferent extruded directions were investigated by testing micro-yield strength (MYS), stress relaxation resistance (SRR), and dimensional change in thermal cycling and unloading conditions.The results show that micro-plastic deformation resistance in longitudinal(parallel to the axis of the extruded bar) direction is higher than that in transverse(perpendicular to the axis of the extruded bar) direction. Testing in short-term loading condition MYS value corresponding to micro-plastic strain of 1 *10m~(-5)in longitudinal direction is 1.4 times than that in transverse.Compared with the results of MYS and dimensional change in thermal cycling and unloading conditions, the values in T6 state are higher than that in T4 state. Using TEM the microstructures before micro-plastic deformation were observed.The analyses confirm that stability of thermodynamics condition and dislocation results in dimensional stability of the alloy.
关键词:
2024 Al alloy
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F. Yang
金属学报(英文版)
Fe/Tb multilayers with various Fe layer thickness and fixed Tb layer thickness wereprepared by e-beam alternate vapor deposition. Analyses of the microstructure of thesefilms show that the magnetic performance is strongly affected by the interface struc-ture. Fe in the films evolved to amorphous phase and the Fe/Tb interface becameindiscernible with decreasing Fe thickness. At the same time, the film was observedto perform superparamagnetically, which is quite different from the ferromagnetic be-havior of Fe/Tb multilayers that have sharp Fe/Tb interface. Our work shows thatthe interface roughness has strong influence to the properties of magnetic multilayers.
关键词:
magnetic multilayer
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