Deformation mechanisms of basal slip, twinning and non-basal slips in Mg-Y alloy by micropillar compression

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:819

Article

Li, Na^1,2  Yang, Lingwei³  Wang, Chuanyun⁴  Monclus, M. A.²  Shi, Dongfeng^2,5  Molina-Aldareguia, J. M.² 

[1] Chinese Acad Sci, Inst Mech, LNM, Beijing 100190, Peoples R China

[2] IMDEA Mat Inst, C Eric Kandel 2, Madrid 28906, Spain

[3] China Aerodynam Res & Dev Ctr, Hyperveloc Aerodynam Inst, Mianyang 621000, Sichuan, Peoples R China

[4] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Peoples R China

[5] Univ Politecn Madrid, Dept Mat Sci, Polytech Univ Madrid, ETS Ingn Caminos, Madrid 28040, Spain

关键词: Magnesium alloy;    Mechanical property;    Micropillar compression;    Deformation mechanisms;   

DOI  :  10.1016/j.msea.2021.141408

来源: Elsevier

【 摘 要 】

Micropillar compression technique was employed to study the microscale deformation mechanisms of basal slip, twinning and non-basal slips at selected grains in a Mg-2 wt.% Y alloy. The results suggest a critical resolved shear stress (tCRSS) for basal slip 12.5 +/- 1.7 MPa, and for twin nucleation and twin growth 38.5 +/- 1.2 MPa and 33.8 +/- 0.7 MPa, respectively. The higher values compared to those in pure Mg suggests a more balanced deformation in Mg alloy with Y addition. The activation of dislocations in the twinned orientation is highlighted, which leads to strong work hardening in twinned favorable orientation [1010]. In addition, at prismatic-slip favorable orientation [1120], a twinning-to-prismatic slip transition was observed when elevating temperature from 25 degrees C to 100 degrees C and 250 degrees C. Specially at 250 degrees C, twinning was completely prohibited, and pure prismatic slip was triggered. The measured tCRSS for prismatic slip at 250 degrees C was 39.7 +/- 0.3 MPa, much higher than that for pure Mg at the same temperature. Finally, at pyramidal-slip favorable orientation [0001], an abnormal strengthening was observed at 100 degrees C and 250 degrees C due to activation of pyramidal slips. Decompositions of dislocations and Y segregation at stacking faults are the main mechanisms leading to the hightemperature strengthening in Mg-Y alloy.

【 授权许可】

Free