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.

Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy Deformed by Multi-Directional Forging with Decreasing Temperature

2021 ◽  
Vol 1035 ◽  
pp. 10-16
Author(s):  
Ying Ze Meng ◽  
Jian Min Yu ◽  
Hui Sheng Yu ◽  
Yao Jin Wu ◽  
Zhi Min Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Dynamic Recrystallization ◽  
Room Temperature ◽  
Forging Process ◽  
Texture Intensity ◽  
Coarse Grains ◽  
Room Temperature Increase ◽  
Zr Alloy

The multi-directional forging process can achieve large plastic deformation, and has great application prospects in industrial production. The Mg-9.55Gd-3.28Y-1.77Zn-0.34Zr (wt%) alloy containing LPSO phase was deformed in different passes and then quenched immediately by the multi-directional forging process with decreasing temperature, and the microstructure and mechanical properties of the alloy were analyzed. It is found that as the number of deformation passes increases, the coarse grains decrease, and the dynamic recrystallization fraction increases. The dynamic recrystallization grains swallow the original grains, promote the continuous refinement of the grains, and greatly improve the uniformity of the microstructure. At the same time, the maximum texture intensity of the (0001) basal plane is significantly reduced, and the pole figure distribution is more dispersed, which is attributed to the random orientation of dynamic recrystallization. Due to the refinement of the microstructure and the weakening of the texture, the tensile strength and yield strength at room temperature increase significantly. After 3 passes of deformation, the alloy has the highest mechanical properties, with tensile strength, yield strength, and elongation reaching 317 MPa, 233 MPa, and 15%, respectively.

scholarly journals Effect of Decreasing Temperature Reciprocating Upsetting-Extrusion on Microstructure and Mechanical Properties of Mg-Gd-Y-Zr Alloy

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 985
Author(s):  
Wenlong Xu ◽  
Jianmin Yu ◽  
Guoqin Wu ◽  
Leichen Jia ◽  
Zhi Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dynamic Recrystallization ◽  
Combined Effect ◽  
Second Phase ◽  
Basal Texture ◽  
Continuous Dynamic Recrystallization ◽  
Texture Intensity ◽  
Fine Grain ◽  
Continuous Dynamic ◽  
Zr Alloy

The decreasing temperature reciprocating upsetting-extrusion (RUE) deformation experiment was carried out on Mg-Gd-Y-Zr alloy to study RUE deformation on the influence of microstructure of the alloy. This work showed that with the gradual increase of RUE deformation passes, the continuous dynamic recrystallization (CDRX) process and the discontinuous dynamic recrystallization (DDRX) process occurred at the same time, and the grain refinement effect was obvious. Particulate precipitation induced the generation of DRX through particle-stimulated nucleation (PSN). In addition, after one pass of RUE deformation, the alloy produced a strong basal texture. As the RUE experiment proceeded, the basal texture intensity decreased. The weakening of the texture was due to the combined effect of DRX and alternating loading forces in the axial and radial directions. After four RUE passes, the mechanical properties of the alloy had been significantly improved, which was the result of the combined effect of dislocation strengthening, fine grain strengthening, and second phase strengthening.

The role of long period stacking ordered phase in dynamic recrystallization of a Mg–Zn–Y alloy during hot compression

2020 ◽  
Vol 818 ◽  
pp. 152814 ◽  
Author(s):  
Tao Chen ◽  
Zhiyong Chen ◽  
Jianbo Shao ◽  
Renke Wang ◽  
Longhui Mao ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Compression ◽  
Long Period

Key Role of the Oxidized Citrate-Free Radical in the Nucleation Mechanism of the Metal Nanoparticle Turkevich Synthesis

2019 ◽  
Vol 123 (36) ◽  
pp. 22624-22633 ◽  
Author(s):  
Sarah Al Gharib ◽  
Jean-Louis Marignier ◽  
Abdel Karim El Omar ◽  
Adnan Naja ◽  
Sophie Le Caer ◽  
...  
Keyword(s):  
Free Radical ◽  
Nucleation Mechanism ◽  
Metal Nanoparticle

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.

Facilitators, challenges and usefulness of an asthma educational programme

2020 ◽  
pp. 001789692098162
Author(s):  
Muhammad Naeem ◽  
Hamad Ghalib Dailah
Keyword(s):  
Cultural Context ◽  
Educational Programme ◽  
Structured Interviews ◽  
Policy Makers ◽  
Long Period ◽  
Breathing Techniques ◽  
Educational Programmes ◽  
Asthma Patients ◽  
Programme Content

Background: This study explored the role of hospitals, specialised doctors and staff in developing patient awareness, participation and motivation concerning asthma control. It also looked at the challenges that undermine the value of asthma educational programmes, especially in an Arab cultural context. Methods: Semi-structured interviews were used to collect data from 30 asthma patients who had been living with asthma for a long period of time. Results: Findings highlight how an asthma educational programme can increase patient knowledge about the causes of asthma. Following the programme, patients had a better understanding of levels of medication, breathing techniques and rest and relaxation. Awareness of support from health professionals for managing depression and frustration also increased. However, some patients felt that the asthma educational programme content and delivery was not very interactive and was too lengthy. Conclusion: Findings can help policy makers, researchers, hospitals, doctors and the national Ministry of Health improve the content of future asthma educational programmes. They can also inform the development of a research framework to extend understanding of relevant issues in an Arabian context.

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