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.

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.

Microstructure and Properties of LPSO Phase Reinforced Mg Alloy Produced by Rheocasting

2016 ◽  
Vol 256 ◽  
pp. 186-191 ◽  
Author(s):  
Shu Lin Lü ◽  
Xiong Yang ◽  
Shu Sen Wu ◽  
Xiao Gang Fang ◽  
Jing Wang
Keyword(s):  
Mechanical Properties ◽  
Squeeze Casting ◽  
Mg Alloy ◽  
Semisolid Slurry ◽  
Strengthening Effect ◽  
Casting Alloy ◽  
Squeeze Pressure ◽  
Lpso Phase ◽  
Long Period ◽  
Refinement Mechanism

The long period stacking ordered (LPSO) phase reinforced Mg alloys have received many researches in recent years because of their excellent mechanical properties. However, the LPSO phase usually concentrates at the grain boundaries with a coarse network structure, which seriously deteriorates its strengthening effect. In this research, rheocasting and ultrasonic vibration (USV) process were firstly used to refine the LPSO phase in Mg alloy. The semisolid slurry of Mg96.9Y2Zn1Zr0.1 (at.%) alloy was prepared by USV and then formed by rheo-squeeze casting (RSC). The effects of USV and squeeze pressure on the microstructure and mechanical properties of this Mg alloy were investigated. The results show that the primary α-Mg and coarse LPSO phases were refined obviously by USV and RSC. The tensile strength and elongation of the RSC Mg96.9Y2Zn1Zr0.1 alloy were 232 MPa and 17.7% respectively, which were increased by 17.8% and 172.3% respectively compared to the conventional liquid casting alloy. The refinement mechanism of the LPSO phase in semisolid Mg alloy is also discussed.

The Effect of Heat Treatment on Microstructure and Mechanical Properties of ZK60 Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 718-721
Author(s):  
Ding Fei Zhang ◽  
Rong Shen Liu ◽  
Jian Peng ◽  
Wei Yuang ◽  
Hong Ju Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Age Hardening ◽  
Second Phase ◽  
Solid Solution Strengthening ◽  
Microstructure And Mechanical Properties ◽  
Long Time ◽  
Zk60 Alloy ◽  
Solution Strengthening

With different heat treatment, the microstructure and mechanical properties of ZK60 magnesium alloy were investigated. It can be concluded that heat treatment has great effect on mechanical properties of ZK60. With artificial aging after extruding, the precipitation of the second phase from the supersaturated solid solution significantly improved mechanical properties. It can greatly increase yield strength of ZK60 alloy, while the tensile strength has little change. For the combination of solid solution strengthening and age hardening, two opposite factors must be considered. On one hand, the solid solution strengthening and the later precipitation strengthening is good for alloy’s strength; on the other hand, the properties decrease as the grains grew under high temperature for a long time during solution heating.

Effect of ZrB2 Nanoparticle Addition: Nano-LPSO-Grain Structured Ultra-High Strength Mg-RE Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 425-430
Author(s):  
Muralidharan Paramsothy ◽  
Manoj Gupta
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Yield Strength ◽  
Polycrystalline Material ◽  
High Strength ◽  
Tensile Yield Strength ◽  
Intermetallic Formation ◽  
Long Period ◽  
Ordered Phases ◽  
The Common

Currently, long period stacking/ordered phases (LPSO phases) are known to reinforceMg97Y2Zn1 type Mg-RE alloys. The LPSO phases are composed of a solid solution of Y and Znatoms placed orderly in long periods along the Mg basal plane. Also, an efficient way to strengthena polycrystalline material is to reduce its grain size. This increases the density of grain boundarieswhich impede the flow of dislocations. In many of the LPSO forming solidification processed Mg-RE alloys, the common practice is to solutionize the ingot, quench in warm water, hot extrude andthermally age. While this practice is suitable for obtaining high strength Mg-RE alloys, itconveniently employs the common idea in conventional metallurgy of fine intermetallicstrengthening while refining the grain size to within the micron regime. In this work, an alternativemethod involving boride nanoparticle addition to obtain a selected solidification processed ultrahighstrength (tensile yield strength > 400 MPa) Mg-RE alloy is discussed. Here, LPSO phaserather than fine intermetallic formation while retaining grain size under the micron regime ishighlighted.

scholarly journals Influence of Long-Period-Stacking Ordered Structure on the Damping Capacities and Mechanical Properties of Mg-Zn-Y-Mn As-Cast Alloys

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4654
Author(s):  
Ruopeng Lu ◽  
Kai Jiao ◽  
Yuhong Zhao ◽  
Kun Li ◽  
Keyu Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Second Phase ◽  
Ordered Structure ◽  
Long Period ◽  
Circular Structure ◽  
Strong Orientation ◽  
Cast Alloys ◽  
Mn Content ◽  
Better Than

Magnesium alloys are concerned for its mechanical properties and high damping performance. The influence of Mn toward the internal organization morphology of long-period stacking ordered (LPSO) second phase and the consistent damping performance in Mg-4.9Zn-8.9Y-xMn have been studies in this work. It has shown that the addition of Mn tends to diffuse to the LPSO interface and causes the LPSO phase to expand in the arc direction. The circular structure of LPSO can optimize the damping property of the alloy better than the structure with strong orientation, especially at the strain of 10−3 and 250 °C. With more additions of Mn, damping would have a reduction due to the dispersed fine LPSO phases and α-Mn particles. When the Mn content is higher than 1.02%, the grain is refined, and mechanical properties have been significantly improved. Mg-4.9%Zn-8.9%Y-1.33%Mn shows the best mechanical property.

scholarly journals Microstructure and Mechanical Properties of Carbide Reinforced TiC-Based Ultra-High Temperature Ceramics: A Review

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1444
Author(s):  
Haobo Mao ◽  
Fuqiang Shen ◽  
Yingyi Zhang ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Solid Solution ◽  
High Temperature ◽  
Bending Strength ◽  
Second Phase ◽  
Strengthening Effect ◽  
Dispersion Strengthening ◽  
The Matrix ◽  
Ultra High Temperature

TiC ceramics have become one of the most potential ultra-high temperature structural materials, because of its high melting point, low density, and low price. However, the poor mechanical properties seriously limit its development and application. In this work, this review follows PRISMA standards, the mechanism of the second phase (particles, whiskers, and carbon nanotubes) reinforced TiC ceramics was reviewed. In addition, the effects of the second phase on the microstructure, phase composition and mechanical properties of TiC ceramics were systematically studied. The addition of carbon black effectively eliminates the residual TiO2 in the matrix, and the bending strength of the matrix is effectively improved by the strengthening bond formed between TiC; SiC particles effectively inhibit the grain growth through pinning, the obvious crack deflection phenomenon is found in the micrograph; The smaller grain size of WC plays a dispersion strengthening role in the matrix and makes the matrix uniformly refined, and the addition of WC forms (Ti, W) C solid solution, WC has a solid solution strengthening effect on the matrix; SiC whiskers effectively improve the fracture toughness of the matrix through bridging and pulling out, the microscopic diagram and mechanism diagram of SiC whisker action process are shown in this paper. The effect of new material carbon nanotubes on the matrix is also discussed; the bridging effect of CNTs can effectively improve the strength of the matrix, during sintering, some CNTs were partially expanded into GNR, in the process of crack bridging and propagation, more fracture energy is consumed by flake GNR. Finally, the existing problems of TiC-based composites are pointed out, and the future development direction is prospected.

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