Solution treatment: A route towards enhancing tensile ductility of SiCp/6061Al composite via powder thixoforming and comparison of micromechanical strength modeling
Solution treatment: A route towards enhancing tensile ductility of SiCp/6061Al composite via powder thixoforming and comparison of micromechanical strength modeling
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DOI：
10.1016/j.msea.2017.04.090
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发表时间：
2017-06
期刊：
影响因子：
6.4
通讯作者：
X. Z. Zhang;T. Chen
中科院分区：
文献类型：
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作者：
X. Z. Zhang;T. Chen
在这项研究中，平均尺寸为6.94 µm的SiC颗粒（SiCp）良好地分散在通过粉末触变成形制备的10vol%SiCp/6061 Al复合材料中，该复合材料结合了粉末冶金和触变成形的优点。复合材料的拉伸强度明显提高，但延伸率较低。而在560 °C × 6 h的固溶处理可以在很大程度上补偿塑性损失（与所制造的复合材料相比，伸长率增加169.2%），（极限抗拉强度和屈服强度分别增加20%和67.2%），这主要是由于改善的韧性基体和由共晶相消失引起的增强的界面结合强度。通过对现有细观强化模型的比较，发现载荷传递机制和固溶强化对屈服强度的贡献最大，揭示了SiCp的加入和固溶处理的重要性。然而，SiCp的强化效率在很大程度上受到其拉伸试验中破坏分数的影响，作者之前提出的模型比其他模型更符合实验结果。这些结果不仅为获得高强度、高塑性的SiCp/6061 Al复合材料提供了一条途径，而且为固溶态复合材料的强度预测提供了更合理的模型。
In this study, SiC particles (SiCp) with a mean size of 6.94 µm were well dispersed in the 10 vol% SiCp/6061Al composite prepared by powder thixoforming that combines the merits of powder metallurgy and thixoforming. The composites had evidently strengthened tensile strength while possessed a low elongation. However, a tailored solution treatment at 560 °C for 6 h can compensate the ductility loss to a large degree (169.2% increment in elongation as compared to the as-fabricated composite) besides an acceptable increment in tensile strength (20% and 67.2% increments in ultimate tensile strength and yield strength, respectively), due mainly to the improved ductile matrix and the enhanced interfacial bonding strength resulting from the disappearance of eutectic phases. According to the comparison results of the existing micromechanical strengthening models, the strength increments resulting from load transfer mechanism and solid solution strengthening contributed most to the yield strength, revealing the significance of SiCpaddition and solution treatment. However, the strengthening efficiency of SiCpwas largely affected by their failure fraction during tensile test and the model that was previously proposed by the authors had a better agreement with the experimental results than the other models. These results not only provided a pathway to achieve high strength SiCp/6061Al composites with enhanced ductility, but also shed light on a more reasonable model for the strength prediction of solutionized composites.