Achieving high strength-ductility combination and negligible yield asymmetry in extruded AlN/AZ91 composite rods
Achieving high strength-ductility combination and negligible yield asymmetry in extruded AlN/AZ91 composite rods
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在挤压 AlN/AZ91 复合材料棒中实现高强度-延展性组合和可忽略的屈服不对称性
DOI：
10.1016/j.msea.2019.138842
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发表时间：
2020-01
期刊：
影响因子：
6.4
通讯作者：
Liu Feng
中科院分区：
文献类型：
--
作者：
Zhang Bin;Yang Changlin;Li Hongxiang;Sun Yunxia;Yan Yize;Zhao Tianhao;Li Xinlin;Liu Feng
传统AZ91基复合材料的强度通常可以通过挤压工艺来提高，但往往会导致延展性不足，这限制了AZ91基复合材料的实际应用。本文通过热挤压工艺显着提高了原位合成法制备的AlN/AZ91复合材料的强度和延展性。微观结构分析表明，原位AlN颗粒促进了再结晶形核并加速了再结晶，导致挤压AlN/AZ91复合材料的晶粒显着细化。通过实验观察发现，AlN颗粒引起的高密度位错促进了热挤压过程中纳米级γ-Mg17Al12相的连续析出。通过理论计算和分析，讨论了不同强化机制对屈服强度增量的贡献，证实晶界强化和沉淀强化是主要的强化机制。通过EBSD辅助滑移迹分析，还证实了挤压AlN/AZ91复合材料中较高的拉伸延展性主要归因于金字塔<c+a>位错滑移系统的激活。此外，由于 AlN 颗粒的原位形成，在挤压的 AlN/AZ91 复合棒中获得了弱的基础织构。然后，挤压 AlN/AZ91 复合材料中的拉伸压缩屈服不对称性可以忽略不计。
The strength of conventional AZ91-based composites can be usually improved by the extrusion process, however the inadequate ductility is often induced, which limits the practical applications of AZ91-based composites. In this paper, the strength and ductility of AlN/AZ91 composites prepared by in situ synthetic method were significantly improved by a hot extrusion process. Microstructural analysis shows that in-situ AlN particles promoted the recrystallization nucleation and accelerated the recrystallization, resulting in a significant grain refinement in the extruded AlN/AZ91 composites. By the experimental observation, it was found that high density dislocations induced by AlN particles promoted the continuous precipitation of nano-sized γ-Mg17Al12phases during the hot extrusion. By theoretical calculation and analysis, the contributions of different strengthening mechanisms on the yield strength increment were discussed, which confirmed that the grain boundary strengthening and precipitation strengthening were mainly strengthening mechanisms. By the EBSD-assisted slip trace analysis, it was also confirmed that the higher tensile ductility in the extruded AlN/AZ91 composites was mainly attributed to the activation of pyramidal <c+a> dislocation slip systems. Additionally, a weak basal texture was obtained in the extruded AlN/AZ91 composite rods due to the in-situ formation of AlN particles. Then a negligible tension-compression yield asymmetry in the extruded AlN/AZ91 composites was obtained.
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影响因子：
10.9
作者：
Yu Qiuhong;Guo-hua Zhou;Liao Lin;Yong Liu;L. Luo
通讯作者：
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DOI：
10.1016/j.msea.2019.138118
发表时间：
2019-08
影响因子：
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作者：
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作者：
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DOI：
10.1016/j.msea.2018.03.126
发表时间：
2018-05
影响因子：
6.4
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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