The Interaction Between $$ \{ 10\bar{1}2\} $$ Twinning and Long-Period Stacking Ordered (LPSO) Phase During Hot Rolling and Annealing Process of a Mg-Gd-Y-Zn-Zr Alloy

2020 ◽  
Author(s):  
Jianbo Shao ◽  
Zhiyong Chen ◽  
Tao Chen ◽  
Chuming Liu
Keyword(s):  
Hot Rolling ◽  
Annealing Process ◽  
Lpso Phase ◽  
Long Period ◽  
Zr Alloy

scholarly journals The Role of Long Period Stacking Ordered Phase in Dynamic Recrystallization of a Mg–Gd–Y–Zn–Zr Alloy during Multi-Directional Forging Process

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3290
Author(s):  
Huiling Liu ◽  
Yingze Meng ◽  
Huisheng Yu ◽  
Wenlong Xu ◽  
Siyang Zhang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Nucleation Site ◽  
Nucleation Mechanism ◽  
Forging Process ◽  
Lpso Phase ◽  
Long Period ◽  
Texture Intensity ◽  
Uniform Microstructure ◽  
Zr Alloy

The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results showed that multi-directional forging can effectively refine the grain with the DRX fraction increased, and DRXed grains lead to the decrease of the texture intensity, which can significantly improve the mechanical properties of the alloy. The different morphologies of the LPSO phase have different degrees of promotion relative to DRX behavior. The lamellar LPSO phase with kinks promoted dislocation plugging, where there could be a potential nucleation site for DRX grains. The fragmented lamellar LPSO phase promoted the DRX process through the particle-stimulated nucleation mechanism, and the block-shaped phase was more prone to stress concentration, which promoted DRX. These effects resulted in continuous grain refinement and a more uniform microstructure.

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.

Effect of Long-Period Stacking Order Phase and α-Mg Phase on Strength and Ductility of Mg-Zn-Y Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1237-1242 ◽  
Author(s):  
Masafumi Noda ◽  
Yoshihito Kawamura
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
High Temperatures ◽  
Mg Alloys ◽  
Tensile Yield Strength ◽  
Block Type ◽  
Lpso Phase ◽  
Long Period ◽  
Stacking Order ◽  
Type Phase

Mg alloys are lightweight structural alloys that normally have a good castability and machinability as well as an excellent specific strength and rigidity. However, the mechanical properties of Mg alloys are inferior to those of Al alloys, and their range of industrial applications is limited. Recently, Mg–Zn–Y alloy has been found to show a high tensile yield strength with a good elongation. The alloy has a long-period stacking order (LPSO) phase as the secondary phase in an α-Mg phase. In general, the tensile yield strengths of LPSO-type Mg alloy are known to be markedly enhanced by the formation of kink bands in the LPSO phase and by microstructural refinement of the α-Mg phase during plastic deformation. The separate roles of the LPSO phase and the α-Mg phase in relation to the mechanical properties of high-strength LPSO-type Mg alloy were investigated at ambient and high temperatures. For high strengths at ambient and high temperatures, it was important that the α-Mg phase consisted of a fine-grain region and a nonrecrystallized region, and that the LPSO phase remained as a block-type phase. On the other hands, it was necessary to change the LPSO phase from a block-type phase into a plate-type phase by heat treatment before tensile testing to improve the ductility of the alloy while maintaining its tensile yield strength. Microstructural control of the LPSO phase and the α-Mg phase is necessary to obtained Mg–Zn–Y alloy with superior mechanical properties at ambient-to-high temperatures.

Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy during Compression

2021 ◽  
Vol 1035 ◽  
pp. 278-285
Author(s):  
Lei Chen Jia ◽  
Jian Min Yu ◽  
Guo Qin Wu ◽  
Wen Long Xu ◽  
Yong Gang Tian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Strain ◽  
Microstructure Evolution ◽  
Large Angle ◽  
Compression Behavior ◽  
Kink Bands ◽  
Long Period ◽  
Different Temperatures ◽  
Compression Temperature ◽  
Zr Alloy

The compression behavior and mechanical properties of the Mg-13Gd-4Y-2Zn-0.5Zr (wt.%) alloy filled with intragranular long-period stacking ordered (LPSO) phases at different temperatures were investigated. The results showed that the higher the compression temperature, the smaller the plastic strain that the grains withstand. The grains changed from equiaxed to flat strips when compressed at 350°C, and the morphology of the grains did not change at 450°C. Due to the existence of DRX grains, compression at 450 °C didn’t cause large-angle kink, but the kink angle at 350°C was very large. DRX grains only appeared at the grain boundaries and around the intergranular LPSO phase at the beginning of compression, and only appear at the kink bands (KBs) after the lamellar LPSO phases begin to kink. DRX grains gradually increased with the KBs increasing.

Formation of a Novel X Phase in Mg–Gd–Zn–Zr Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 623-626 ◽  
Author(s):  
Y.J. Wu ◽  
Li Ming Peng ◽  
X.Q. Zeng ◽  
D.L. Lin ◽  
W.J. Ding
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformation ◽  
Grain Boundaries ◽  
Solution Heat Treatment ◽  
Long Period ◽  
Β Phase ◽  
Lpso Structure ◽  
Zr Alloy ◽  
Zr Alloys

The coherent fine-lamellae consisting of the 2H-Mg and the 14H-type long period stacking ordered (LPSO) structure within α'-Mg matrix have been observed in an as-cast Mg–Gd–Zn–Zr alloy. During subsequent solid solution heat treatment at 773 K, in addition to the lamellae within matrix, a novel lamellar X phase [Mg–(8.37±1.0)Zn–(11.32±1.0)Gd] with the 14H-type LPSO structure was transformed from the dendritical β phase. The 14H-type LPSO structure existing in Mg–Gd–Zn–Zr alloys derives from two variant ways: formation of the 14H-type LPSO structure comes from two variant means: i.e., the formation within matrix and the phase transformation from the β phase to the X phase in grain boundaries.

Ultrasonic Rheocasting for Refinement of Mg Alloys Reinforced with LPSO Phase

2018 ◽  
Vol 941 ◽  
pp. 1607-1612 ◽  
Author(s):  
Shu Lin Lü ◽  
Xiong Yang ◽  
Liang Yan Hao ◽  
Shu Sen Wu
Keyword(s):  
Mechanical Properties ◽  
Squeeze Casting ◽  
Mg Alloys ◽  
Average Thickness ◽  
Squeeze Pressure ◽  
Lpso Phase ◽  
Long Period ◽  
Lpso Structure ◽  
Cast Alloys ◽  
Gravity Cast

In this work, ultrasonic rheocasting was used to refine the microstructures of Mg alloys reinforced with long period stacking ordered (LPSO) phase. The semisolid slurries of Mg-Zn-Y and Mg-Ni-Y alloys were prepared by ultrasonic vibration (UV) and then formed by rheo-squeeze casting under high squeeze pressure (~ 400 MPa). The effects of UV and squeeze pressure on microstructure and mechanical properties of the Mg alloys were studied. The results reveal that UV and rheo-squeeze casting can significantly refine the LPSO structure and alpha-Mg matrix in Mg alloys, but they cannot change the phase compositions of the alloys or the type of LPSO phase. When the squeeze pressure is 400 MPa, the average thickness of LPSO phase is decreased, and the block LPSO structure is completed eliminated and uniformly distributed at the grain boundaries. Compared with the gravity cast alloys without UV, mechanical properties of the rheocast Mg alloys were enhanced and reached the maximums when the squeeze pressure was 400 MPa.

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.

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