Relationship of particle stimulated nucleation, recrystallization and mechanical properties responding to Fe and Si contents in hot-extruded 7055 aluminum alloys
Relationship of particle stimulated nucleation, recrystallization and mechanical properties responding to Fe and Si contents in hot-extruded 7055 aluminum alloys
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DOI：
10.1016/j.jmst.2019.07.014
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发表时间：
2019-10
影响因子：
10.9
通讯作者：
Shen Huan;Shu Da;Dong Anping;W. Jun;Sun Bao-de;Lai Hongchang
中科院分区：
文献类型：
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作者：
Shen Huan;Shu Da;Dong Anping;W. Jun;Sun Bao-de;Lai Hongchang
研究了热挤压7055铝合金中粗金属间化合物颗粒的变化规律，合金中Fe和Si的质量分数分别为0.041wt%，0.024wt%，0.272wt%，0.134wt%，0.272wt%，0.134wt%。利用EBSD技术对不同类型粗颗粒的颗粒激发成核行为进行了详细的分析。此外，还研究了Fe和Si含量对7055合金再结晶和拉伸性能的影响。随着Fe和Si含量的增加，η/S粗颗粒的尺寸和数密度减小，而Al 7 Cu 2Fe和Mg 2Si粗颗粒的数密度均增大，Al 7 Cu 2Fe粗颗粒由棒状向不规则形转变。不规则的Al 7 Cu 2Fe和Mg 2Si颗粒刺激了更多的PSN再结晶晶粒，其主导取向偏离挤压纤维织构，因为产生了更高程度的局部不均匀变形。棒状的Al 7 Cu 2Fe颗粒由于其最大的长径比而导致最大程度的局部不均匀变形，但其形状也限制了颗粒变形区（PDZ）的面积，导致较少的PSN再结晶晶粒。不规则的η/S颗粒导致最低程度的局部不均匀变形和最少的PSN再结晶晶粒，其主要取向接近挤出纤维织构。结果表明，随着Fe和Si含量的增加，尽管粗大的η/S颗粒数量和尺寸减少，但由于Al 7 Cu 2Fe和Mg 2Si颗粒的增加，大角度晶界（HAGB）比例增加，挤压纤维织构减弱。强度略有下降的<111>削弱//艾德（挤压方向）的纤维织构，而伸长率降低了大量的粗颗粒和更多的HAGB具有较高的Fe和Si含量。
The variations of coarse intermetallic particles in hot-extruded 7055 aluminum alloys with 0.041 wt% Fe and 0.024 wt% Si increasing to 0.272 wt% Fe and 0.134 wt% Si were investigated. The particle stimulated nucleation (PSN) behaviors for different kind of coarse particles were detailly analyzed by EBSD. Moreover, the effect of PSN responding to Fe and Si contents on recrystallization and tensile properties of 7055 alloys was evaluated. With increasing Fe and Si contents, the size and number density of coarse η/S particles are reduced, while the number densities of coarse Al7Cu2Fe and Mg2Si particles are both increased and the coarse Al7Cu2Fe particles transform from rod-like to irregular. More PSN recrystallized grains with predominant orientations deviated from the extruded fiber textures are stimulated by the irregular Al7Cu2Fe and Mg2Si particles, because a higher degree of local non-uniform deformation is produced. The rod-like Al7Cu2Fe particles cause the greatest degree of local non-uniform deformation owing to the largest aspect ratio, but the shape also restricts the area of particle deformation zone (PDZ) resulting in fewer PSN recrystallized grains. The irregular η/S particles give rise to the lowest degree of local non-uniform deformation and fewest PSN recrystallized grains with the major orientations close to the extruded fiber textures. Consequently, despite the number and size of coarse η/S particles are reduced, the proportion of high angle grain boundaries (HAGBs) is increased and the extruded fiber textures are weakened with Fe and Si contents increasing, because of the increased Al7Cu2Fe and Mg2Si particles. The strength is slightly declined by the weakened <111>//ED (extrusion direction) fiber texture, while the elongation is reduced for a larger number of coarse particles and more HAGBs with higher Fe and Si contents.