Cottrell atmospheres along dislocations in long-period stacking ordered phases in a Mg–Zn–Y alloy

2016 ◽  
Vol 117 ◽  
pp. 77-80 ◽  
Author(s):  
W.W. Hu ◽  
Z.Q. Yang ◽  
H.Q. Ye
Keyword(s):  
Long Period ◽  
Ordered Phases ◽  
Cottrell Atmospheres

scholarly journals A Study on the Damping Capacities of Mg–Zn–Y-Based Alloys with Lamellar Long Period Stacking Ordered Phases by Preparation Process

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Ruopeng Lu ◽  
Kai Jiao ◽  
Yuhong Zhao ◽  
Kun Li ◽  
Keyu Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Damping Capacity ◽  
Second Phase ◽  
Preparation Process ◽  
Obvious Effect ◽  
Lpso Phase ◽  
Long Period ◽  
Lamellar Phases ◽  
Ordered Phases

Mg alloys with fine mechanical properties and high damping capacities are essential in engineering applications. In this work, Mg–Zn–Y based alloys with lamellar long period stacking ordered (LPSO) phases were obtained by different processes. The results show that a more lamellar second phase can be obtained in the samples with more solid solution atoms. The density of the lamellar LPSO phase has an obvious effect on the damping of the magnesium alloy. The compact LPSO phase is not conducive to dislocation damping, but sparse lamellar phases can improve the damping capacity without significantly reducing the mechanical properties. The Mg95.3Zn2Y2.7 alloy with lamellar LPSO phases and ~100 μm grain size exhibited a fine damping property of 0.110 at ε = 10–3.

scholarly journals Increase in the Mechanical Strength of Mg-8Gd-3Y-1Zn Alloy Containing Long-Period Stacking Ordered Phases Using Equal Channel Angular Pressing Processing

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 221 ◽  
Author(s):  
Gerardo Garces ◽  
Pablo Pérez ◽  
Rafael Barea ◽  
Judit Medina ◽  
Andreas Stark ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Yield Stress ◽  
Equal Channel Angular Pressing ◽  
Volume Fraction ◽  
Extrusion Direction ◽  
Grain Structure ◽  
Long Period ◽  
Angular Pressing ◽  
Β Phase ◽  
Ordered Phases

The evolution of the microstructure and mechanical properties during equal channel angular pressing processing has been studied in an extruded Mg-Gd-Y-Zn alloy containing long-period stacking ordered phases. After extrusion, the microstructure is characterized by the presence of long-period stacking ordered fibers elongated along the extrusion direction within the magnesium matrix. The grain structure is a mixture of randomly oriented dynamic recrystallized and coarse highly oriented non-dynamic recrystallized grains. Rare-earth atoms are in solid solution after extrusion at 400 °C and precipitation takes place during the thermal treatment at 200 °C. Precipitation of β’ prismatic plates and lamellar γ’ in the basal plane increases the tensile yield stress from 325 to 409 MPa. During equal channel angular pressing processing at 300 °C, the volume fraction of dynamic recrystallized grains continuously increases with the strain introduced during the equal channel angular pressing process. Precipitation of β phase is equally observed at grain boundaries of the ECAPed alloy. Dynamic recrystallized grain size decreases from 1.8 µm in the extruded material to 0.5 µm in the ECAPed alloy. Thermal treatment at 200 °C of ECAPed materials results in an increase of the yield stress up to 456 MPa, which is maintained up to 200 °C.

Mg-Zn-Y Alloys with Long-Period Stacking Ordered Phases: Deformation, Creep, Solute Segregation and Strengthening Mechanisms at Elevated Temperatures

2016 ◽  
Vol 879 ◽  
pp. 2204-2209 ◽  
Author(s):  
Zhi Qing Yang ◽  
Wei Wei Hu ◽  
Heng Qiang Ye
Keyword(s):  
Plastic Deformation ◽  
Creep Resistance ◽  
Basal Slip ◽  
Elevated Temperatures ◽  
Stacking Faults ◽  
Dislocation Motion ◽  
Tensile Creep ◽  
Lpso Phase ◽  
Long Period ◽  
Cottrell Atmospheres

Mg-Zn-Y alloys with long-period stacking ordered (LPSO) phases have superior strength at elevated temperatures. We studied plastic deformation and creep behavior of a Mg97Zn1Y2 (at.%) alloy. Deformation kinking of the LPSO phase plays an important role in strengthening the alloy during compression at elevated temperatures. Growth stacking faults with Zn/Y segregation can act as obstacles to non-basal slip and deformation twinning in Mg matrix. The tensile creep strain was only about 0.01% under a tensile stress of 70MPa for 100h at 200 °C, demonstrating excellent creep resistance of this alloy. Generation and motion of basal dislocations led to bending of LPSO phase during tensile creep of the Mg97Zn1Y2 (at.%) alloy. Plastic deformation in Mg grains was mostly achieved through basal slip during creep at temperatures below 200 °C, while non-basal slip through the generation and motion of “a + c” dislocations was activated with increasing the temperature to 200 °C and above. Dissociation of dislocations and Suzuki segregation on basal planes occurred widely in Mg matrix, which hindered dislocation motion and thus played an important role in preventing Mg grains from softening during deformation at elevated temperatures. In addition, Cottrell atmospheres were observed along dislocations in plastically deformed LPSO phase, impeding motion of dislocations. The superior strength and creep resistance of the Mg97Zn1Y2 (at.%) alloy at elevated temperatures are thus associated with the LPSO phase, stacking faults in Mg grains, formation of Cottrell atmospheres in LPSO and occurrence of Suzuki segregation in Mg.

Hot compression behavior of the Mg-Gd-Y-Zn-Zr alloy filled with intragranular long-period stacking ordered phases

2017 ◽  
Vol 724 ◽  
pp. 528-536 ◽  
Author(s):  
Xiaojie Zhou ◽  
Chuming Liu ◽  
Yonghao Gao ◽  
Shunong Jiang ◽  
Wenhui Liu ◽  
...  
Keyword(s):  
Hot Compression ◽  
Compression Behavior ◽  
Long Period ◽  
Ordered Phases ◽  
Zr Alloy
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