Simultaneously improving the strength and ductility of AZ91/GNPs composites through decorating graphene nanoplatelets with MgO  

作　　者：Pingbo Wang Jun Shen Tijun Chen Jiqiang Ma Qinglin Li Shaokai Zheng 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [2]State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

出　　处：《Journal of Materials Science & Technology》2024年第16期133-151,共19页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51761028);the Natural Science Foundation of Gansu Province,China(No.21JR7RA232).

摘　　要：Magnesium matrix composites(MgMCs)have always suffered low strengthening efficiency and poor ductility due to the difficulties in pursuing the well-bonded interface.Herein,graphene nanoplatelets(GNPs)were decorated with magnesium oxide nanoparticles(MgO NPs)through chemical co-precipitation and then incorporated into AZ91 alloy to fabricate MgMCs via powder thixoforging.The effect of MgO on the interface of the Mg/graphene system was investigated based on the first-principles calculations,and the result indicated that modifying GNPs with MgO NPs was helpful in improving the Mg-GNP interface bonding.The interface structural analysis revealed that the MgO NPs were firmly bonded with both GNPs andα-Mg through the distortion area bonding and semi-coherent interfacial bonding,severing as a bridge to fasten the interface bonding of composites.In addition,the MgO NPs on GNPs acted as a barrier to prevent GNPs from seriously reacting with the AZ91 alloy.As a result,the AZ91/MgO@GNPs composite was endowed with enhancements of 31%and 10%in the yield strength,and increments of 71%and 61%in elongation compared with the AZ91 alloy and AZ91/GNPs composite,respectively,exhibiting a more significant potential in optimizing the strength-toughness tradeoffcompared with the AZ91/GNPs.Moreover,the possible strengthening and toughening mechanisms were also discussed in detail.This work offers a relatively novel surface modification strategy to modulate the Mg-GNP interface for a simultane-ous improvement of strength and ductility.

关 键 词：Graphene nanoplatelets Magnesium oxide First-principles calculations Magnesium matrix composites Powder thixoforging 

分 类 号：TG146.23[一般工业技术—材料科学与工程]