The effects of Cu content on the toughness and bendability of Al-1Mg-0.6Si-xCu alloy sheet were investigated by means of tensile testing,Kahn tearing and bending experiments,in conjunction with digital image correlation analysis(DIC)and scanning transmission electron microscopy(STEM).The results show that with the increase of Cu content,the elongation,uniform elongation,uniform fracture energy and unit initiation energy(UIE)of the alloys gradually increase.The bendability of the alloy is improved,and the toughness during the uniform stage is enhanced.Conversely,the buckling elongation,buckling fracture energy and unit propagation energy(UPE)of the alloys decrease with higher Cu contents,leading to deteriorated buckling toughness of the alloys.As Cu content in the Al-1Mg-0.6Si-xCu alloy increases,the nucleation sites of the strengthening phase β″ increases,and the Q′ and L phases appear in 0.5-Cu alloy.The increasing density of matrix precipitates raises the energy consumption during deformation,while the increased spacing between grain boundary precipitates improves the toughness and bendability of the alloy.
关键词
Al-Mg-Si-Cu合金/Cu含量/失稳伸长率/裂纹形核功/裂纹扩展功/弯曲性能
Key words
Al-Mg-Si-Cu alloy/Cu content/elongation of buckling/unit initiation energy/unit propagation energy/bendability
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