Cr和Mn对汽车用铝合金型材压溃性能的影响

Effect of Cr and Mn on Crushing Properties of Aluminum Alloy Profiles for Automobile

本工作利用型材在全截面压缩过程中的塑性变形行为研究了Cr和Mn含量对汽车用铝合金型材压溃性能的影响。结果表明:Cr和Mn的添加能有效抑制挤压过程中基体再结晶的发生与晶粒的长大。Cr和Mn含量为0.09%(质量分数,下同)时,型材截面为完全粗晶组织;Cr和Mn含量为0.23%时,型材截面仅存在厚度约400 μm的粗晶层;Cr和Mn含量为0.51%时,型材整个截面为均匀细小纤维状组织。具有细晶组织特征的型材在变形后期会出现明显的以颈缩为特征的非均匀塑性变形行为,整个过程产生约4%的延伸率(A_(50)),其显著提升了材料的局部变形能力。与粗晶组织型材压溃吸能(5.5 kJ)相比,细晶组织型材压溃吸能(10.6 kJ)提升,可见细晶组织表现出更加优异的碰撞吸能效果。

In this work,the effect of Cr and Mn content on the collapsibility of aluminum alloy profiles for automobile was studied by using the plastic deformation behavior of profiles during full section compression.The results show that the addition of Cr and Mn can effectively inhibit the recrystallization and grain growth during extrusion.When the content of Cr and Mn is 0.09%,the profile is completely coarse-grained;as the content of Cr and Mn is 0.23%,there are only coarse grain layers with a thickness of 400μm;while the content of Cr and Mn is 0.51%,the whole section of the profile is uniform and has fine fibrous structure.In the later stage of deformation,the non-uniform plastic deformation behavior cha-racterized by necking is obvious for profiles with fine grain structure.This stage produces about 4%(A_(50))elongation,which greatly improves the local deformation ability of profiles.The crushing energy of fine-grained profiles(10.6 kJ)increases,compared with that of coarse-grained profiles(5.5 kJ).Evidently,the fine grains show a better energy absorption effect.