TY - JOUR

T1 - Microstructural evolution of Mg–14Gd–0.4Zr alloy during compressive creep

AU - Shi, Hui

AU - Huang, Yuanding

AU - Yang, Lixiang

AU - Liu, Chunquan

AU - Dieringa, Hajo

AU - Lu, Chong

AU - Xiao, Lv

AU - Willumeit-Römer, Regine

AU - Hort, Norbert

N1 - Funding Information: Thanks to the Shanghai Sailing Program (23YF1417100), National Natural Science Foundation of China ( U2037601 ), as well as China Scholarship Council (Grant No: 202006890008 ) for the financial support. Hui Shi wishes to thank the meaningful discussions on TEM characterizations and analyses with Dr. Chong Lu and Dr. Chunquan Liu, on OM and SEM characterizations with Dr. Sarkis Gavras, Mr. Gert Wiese and Ms. Petra Fischer, on XRD tests with Dr. Maria Serdechnova, as well as on composition test with Mr. Daniel Strerath in this study. Publisher Copyright: © 2023

PY - 2023/9/1

Y1 - 2023/9/1

N2 - The present work reports the creep behavior and microstructural evolution of the sand-cast Mg–14Gd–0.4Zr alloy (wt.%) prepared by the differential pressure casting machine. Their compressive creep tests at 250 °C were performed under various applied stresses (i.e., 60, 80 and 100 MPa). Among them, the sand-cast Mg–14Gd–0.4Zr samples examined under 250 °C/80 MPa for 39 and 95 h, respectively, were chosen to systemically analyze their creep mechanisms using high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The obtained results showed that the enhancement of creep resistance can be mainly attributed to the coherent β' and β'F phases with an alternate distribution, effectively impeding the basal dislocations movement. However, with the creep time increasing, the fine β'+β'F precipitate chains coarsened and transformed to semi-coherent β1 phase and even to large incoherent β phase (surrounded by precipitate-free areas) in grain interiors. The precipitate-free zones (PFZs) at grain boundaries (GBs) were formed, and they could expand during creep deformation. Apart from the main cross-slip of basal and prismatic dislocations, type dislocations were activated and tended to distribute near the GBs. The aforementioned phenomena induced the stress concentrations, consequently leading to the increment of the creep strain.

AB - The present work reports the creep behavior and microstructural evolution of the sand-cast Mg–14Gd–0.4Zr alloy (wt.%) prepared by the differential pressure casting machine. Their compressive creep tests at 250 °C were performed under various applied stresses (i.e., 60, 80 and 100 MPa). Among them, the sand-cast Mg–14Gd–0.4Zr samples examined under 250 °C/80 MPa for 39 and 95 h, respectively, were chosen to systemically analyze their creep mechanisms using high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The obtained results showed that the enhancement of creep resistance can be mainly attributed to the coherent β' and β'F phases with an alternate distribution, effectively impeding the basal dislocations movement. However, with the creep time increasing, the fine β'+β'F precipitate chains coarsened and transformed to semi-coherent β1 phase and even to large incoherent β phase (surrounded by precipitate-free areas) in grain interiors. The precipitate-free zones (PFZs) at grain boundaries (GBs) were formed, and they could expand during creep deformation. Apart from the main cross-slip of basal and prismatic dislocations, type dislocations were activated and tended to distribute near the GBs. The aforementioned phenomena induced the stress concentrations, consequently leading to the increment of the creep strain.

KW - Creep property

KW - Dislocation

KW - Magnesium alloys

KW - Microstructures

KW - Precipitate chains

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85173254374&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/4b47715c-8d9f-3f23-b202-1701d0c51d28/

U2 - 10.1016/j.jma.2023.09.005

DO - 10.1016/j.jma.2023.09.005

M3 - Journal articles

AN - SCOPUS:85173254374

VL - 11

SP - 3161

EP - 3173

JO - Journal of Magnesium and Alloys

JF - Journal of Magnesium and Alloys

SN - 2213-9567

IS - 9

ER -