Effects of multimodal microstructure on fracture toughness and its anisotropy of LPSO-type extruded Mg-1Zn-2Y alloys  

作　　者：Soya Nishimoto Taiga Yasuda Koji Hagihara Michiaki Yamasaki 

机构地区：[1]Department of Materials Science,Graduate School of Science and Technology,Kumamoto University,2-39-1 Kurokami,Chuo-ku,Kumamoto 860-8555,Japan [2]Magnesium Research Center,Kumamoto University,2-39-1 Kurokami,Chuo-ku,Kumamoto 860-8555,Japan [3]Department of Physical Science and Engineering,Nagoya Institute of technology,Gokiso-cho,Showa-ku,Nagoya 466-8555,Japan

出　　处：《Journal of Magnesium and Alloys》2024年第7期2952-2966,共15页镁合金学报（英文）

基　　金：supported by the JST CREST for Research Area“Nanomechanics”[JPMJCR2094];the JSPS KAKENHI for Scientific Research B[JP21H01673];the AMADA Foundation[AF-2023044-C2].

摘　　要：The fracture toughness of extruded Mg-1Zn-2Y(at.%)alloys,featuring a multimodal microstructure containing fine dynamically recrystallized(DRXed)grains with random crystallographic orientation and coarse-worked grains with a strong fiber texture,was investigated.The DRXed grains comprised randomly oriented equiaxedα-Mg grains.In contrast,the worked grains includedα-Mg and long-period stacking ordered(LPSO)phases that extended in the extrusion direction(ED).Both types displayed a strong texture,aligning the(10.10)direction parallel to the ED.The volume fractions of the DRXed and worked grains were controlled by adjusting the extrusion temperature.In the longitudinal-transverse(L-T)orientation,where the loading direction was aligned parallel to the ED,there was a tendency for the conditional fracture toughness,KQ,tended to increase as the volume fraction of the worked grains increased.However,the KQ values in the T-L orientation,where the loading direction was perpendicular to the ED,decreased with an increase in the volume fraction of the worked grains.This suggests strong anisotropy in the fracture toughness of the specimen with a high volume fraction of the worked grains,relative to the test direction.The worked grains,which included the LPSO phase and were elongated perpendicular to the initial crack plane,suppressed the straight crack extension,causing crack deflection,and generating secondary cracks.Thus,these worked grains significantly contributed to the fracture toughness of the extruded Mg-1Zn-2Y alloys in the L-T orientation.

关 键 词：Magnesium alloy Magnesium-zinc-yttrium Long-period stacking ordered phase Multimodal microstructure Fracture toughness 

分 类 号：TG379[金属学及工艺—金属压力加工] TG146.22[一般工业技术—材料科学与工程]