Effect of characteristics and distribution of Mg17Al12 precipitates on tensile and bending properties of high-Al-containing Mg alloys

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外文摘要：This study investigates the effect of characteristics and distribution of Mg17Al12 precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The extruded Mg-9Al-1Zn-0.3Mn(AZ91)alloy contains lamellar-structured Mg17Al12 discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air cooling.The extruded Mg-11Al-1Zn-0.3Mn(AZ111)alloy contains spherical Mg17Al12 precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during extrusion.Due to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions: precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser grains.The AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates re-sult in stronger grain-boundary hardening and precipitation hardening effects,respectively.However,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and propagation.During bending,a macrocrack initiates on the outer surface of bending specimen in both alloys.The AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 alloy.The bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the specimen.In bending specimens of the AZ111 alloy,it is found that the failure ben-ding strain(εf,bending)is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(Appt),with a relationship of εf,bending=-0.1Appt+5.86.

外文关键词：

Mg-Al alloyExtrusionBendingPrecipitationMicrostructure

作者：

Sumi Jo、Gyo Myeong Lee、Jong Un Lee、Young Min Kim、Sung Hyuk Park

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作者单位：

School of Materials Science and Engineering,Kyungpook National University,Daegu 41566,Republic of Korea

Department of Magnesium,Korea Institute of Materials Science,Changwon 51508,Republic of Korea

基金：

National Research Foundation of KoreaNational Research Foundation of KoreaNational Research Foundation of KoreaMinistry of Science,ICT,and Future Planning(MSIP,South Korea)

项目编号：

NRF2019R1A2C1085272RS-2023-00244478

出版年：

2024

DOI：

10.1016/j.jma.2024.01.018

镁合金学报(英文)

ISSN：2213-9567

年,卷(期)：2024.12(2)

参考文献量61