Interfacial structure in AZ91 alloy composites reinforced by graphene nanosheets
Interfacial structure in AZ91 alloy composites reinforced by graphene nanosheets
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DOI：
10.1016/j.carbon.2017.10.090
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发表时间：
2018-02
期刊：
影响因子：
10.9
通讯作者：
Yu Qiuhong;Guo-hua Zhou;Liao Lin;Yong Liu;L. Luo
中科院分区：
文献类型：
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作者：
Yu Qiuhong;Guo-hua Zhou;Liao Lin;Yong Liu;L. Luo
石墨烯纳米片(GNS)具有优异的力学性能和较高的成品率，是制备块体石墨烯-金属复合材料的最有前途的纳米增强材料。然而，由于GNS的界面结合不良和团聚现象，有效地合成这种块体石墨烯增强镁(MG)复合材料仍然具有挑战性。在这里，GNS拥有约12%的股份。采用热还原法合成了残氧量为7：1的∼催化剂。GNS中的这些残余氧有利于通过纳米氧化镁颗粒增强GNS与α-Mg之间的界面结合，这种纳米颗粒是通过残余氧与α-Mg发生反应而合成的。透射电子显微镜分析表明，原位合成的纳米氧化镁由于形成了α/α-Mg的半共格界面和变形区界面，显著改善了界面结合性能。当GNS含量为0.5wt%时，复合材料的屈服强度和延伸率较基体合金分别提高了76.2%和24.3%。复合材料力学性能的显著提高主要是由于晶粒细化、界面结合强烈和位错强化。
Graphene nanosheets (GNS) are the promising nano-reinforcements to fabricate bulk graphene-metal composites due to their excellent mechanical properties and large yield. However, the effective synthesis of such bulk graphene reinforced magnesium (Mg) composites remains challenging because of the poor interfacial bonding and the aggregation of GNS. Here, GNS possessing about 12 at. % residual oxygen (∼7:1 C/O ratio) was synthesized by a thermal reduction method. These residual oxygen in GNS is beneficial to increase the interfacial bonding between GNS and the matrix of α-Mg by MgO nanoparticles, which synthesized through the occurrence of a reaction between the residual oxygen and α-Mg in the composites. TEM analysis reveals that the in-situ synthesized MgO nanoparticles can significantly improve the interfacial bonding between GNS and α-Mg owing to the formation of semi-coherent interface of MgO/α-Mg and the distortion area bonding interface of GNS/MgO. By filling 0.5 wt. % of GNS, the yield strength and elongation of the composite increased by 76.2% and 24.3%, respectively as compared to the matrix alloy. The significant improvement in mechanical properties of the composites is mainly due to the grain refinement, strong interfacial bonding and dislocation strengthening.