Fabrication of graphene nanoplatelets reinforced Mg matrix composites via powder thixoforging  

作　　者：Pingbo Wang Jun Shen Tijun Chen Qinglin Li Xiao’an Yue Lingyun Wang 

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 Magnesium and Alloys》2022年第11期3113-3132,共20页镁合金学报（英文）

基　　金：financially supported by the National natural Science Foundation of China (Grant No.51761028)。

摘　　要：A powder thixoforging route combined with slurry based mixing process was proposed to fabricate graphene nanoplatelets(GNPs) reinforced magnesium matrix composites(MgMCs). The originally spherical and ball-milled ZK60 powders were used as matrices, respectively.The mixing of 0.05 wt.% GNPs with the spherical powder led to GNPs clusters and degraded the mechanical properties of the composite.In contrast, with the addition of an optimal content(0.1 wt.%) of GNPs, the composite fabricated from ball-milled powder achieved a joint enhancement in tensile yield strength(52%) and fracture toughness(19%), demonstrating a pronounced strengthening efficiency of 650% and a good balance between strength and toughness. The ball-milled powder endowed the composite with a homogenous distribution of GNPs and a denser microstructure with reduced Mg-Zn eutectics, and the thixoforging process offered a well-bonded Mg/GNP interface, making full use of the strengthening and toughening potential of GNPs. Theoretical predication based on a modified shear-lag model suggested that load transfer dominated the strengthening mechanisms. In-situ tensile tests verified that crack deflection, secondary cracks and GNPs bridging mainly accounted for the toughening mechanisms. A numerical model with consideration of GNPs orientations was also established to understand the toughening effect from GNPs bridging.

关 键 词：Graphene nanoplatelets(GNPS) MAGNESIUM Powder thixoforging Strengthening TOUGHENING 

分 类 号：TB333[一般工业技术—材料科学与工程]