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

作　　者：Hui Shi Yuanding Huang Lixiang Yang Chunquan Liu Hajo Dieringa Chong Lu Lv Xiao Regine Willumeit-Römer Norbert Hort 

机构地区：[1]Institute of Metallic Biomaterials,Helmholtz-Zentrum Hereon,Max-Planck-Str.1,Geesthacht 21502,Germany [2]Research and Development Center,Shanghai Spaceflight Precision Machinery Research Institute,Shanghai 201600,China [3]School of Mechanical Engineering,Guizhou University,Guiyang 550025,China [4]Institute of Material and Process Design,Helmholtz-Zentrum Hereon,Max-Planck-Str.1,Geesthacht 21502,Germany [5]The Instrument Analysis Center,Shanghai Jiaotong University,Shanghai 200240,China [6]Institute of Product Technology and Systems,Leuphana University Lüneburg,Universitätsallee 1,Lüneburg D 21335,Germany

出　　处：《Journal of Magnesium and Alloys》2023年第9期3161-3173,共13页镁合金学报（英文）

基　　金：the Shanghai Sailing Program (23YF1417100);National Natural Science Foundation of China (U2037601);China Scholarship Council (Grant No: 202006890008) for the financial support。

摘　　要：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 ℃ were performed under various applied stresses(i.e., 60, 80 and100 MPa). Among them, the sand-cast Mg-14Gd-0.4Zr samples examined under 250 ℃/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 β_1 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.

关 键 词：Magnesium alloys Creep property MICROSTRUCTURES Precipitate chains DISLOCATION 

分 类 号：TG146.22[一般工业技术—材料科学与工程]