Correlation between Solidified Microstructure Evolution and Undercooling of Au-12 Wt.%Ge Eutectic Alloy

2020 ◽  
Vol 993 ◽  
pp. 53-59
Author(s):  
Zhen Yong Zhu ◽  
Kai Xiong ◽  
Jun Jie He ◽  
Shun Meng Zhang ◽  
Si Yong Xu ◽  
...  

Highly undercooled solidification experiments were carried out by melt purification combined with cyclic superheating method on Au-12 wt.%Ge eutectic alloy. The solidification structures of Au-12 wt.%Ge eutectic alloy under different undercoolings were also analyzed by using the scanning electron microscope (SEM). The experimental results revealed that the maximum undercooling could reach up to 102 K. The microstructure analysis showed that the coarse bulk eutectic existed in the solidification structure when the undercooling was less than 34 K. When the undercooling was larger than 34 K and less than 56 K, the solidification structure transformed into cellular eutectic. The coarse primary (α-Au) phase precipitated from the undercooled alloy melt when the undercooling was larger than 56 K. The volume fraction of the primary (α-Au) phase gradually increased with the increase of undercooling. In this paper, a method to regulate the solidification structure of Au-12 wt.%Ge eutectic alloy is proposed, which provides a new way to improve the solidification structure and has important guiding significance for the processing and forming process of Au-12 wt.%Ge eutectic alloy.

2007 ◽  
Vol 546-549 ◽  
pp. 241-244 ◽  
Author(s):  
Yun Qi Yan ◽  
H. Zhang ◽  
Q. Chen ◽  
H. Zhong ◽  
W.P. Weng

Rolling and punching techniques of AZ31 alloy were investigated in this paper. Various rolling experiments were carried out to make fine-grained Mg sheets. Punching tests were conducted at the temperatures range from 70 to 300 oC. The analysis revealed that there existed an excellent warm forming temperature for as-rolled AZ31 alloy. A warm deep punching tool setup using heating elements was designed and manufactured to produce the cell phone. Microstructures were observed using optical and scanning electron microscope equipped with EBSD. The textures in as-rolled and as-annealed specimens attribute to different mechanical properties along the various direction.


2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaojian Cao ◽  
Han Zhang ◽  
Jun Yu ◽  
Tianchong Yu ◽  
Yuxing Qing

Determination of the mechanical properties of rock containing pre-existing cracks under tension condition is of great significance to understand the failure process of rock in engineering. This paper presents the experimental results of sandstone containing pre-existing cracks under Brazilian compression. The characteristics of the microcracks were analyzed by a scanning electron microscope. The results show that the rock containing pre-existing cracks has an obvious anisotropic characteristic. When the crack inclination is 45°, the rock has the minimum tensile strength and the weakest axial deformation resistance.


2011 ◽  
Vol 63 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Z. R. Sun ◽  
M. Gao ◽  
Y. Z. Peng ◽  
X. Hu

Electrochemical dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution was investigated on palladium-loaded meshed titanium (Pd/Ti) electrode at ambient temperature. Pd/Ti electrode was prepared with an electrodepositing method. Scanning Electron Microscope (SEM) micrographs show that Pd microparticles uniformly disperse on the meshed Ti supporting electrode with spheroidal structure. Dechlorination experimental results indicate that, in aqueous solution, with the current efficiency of 24.3%, the removal efficiency of 100 mg/L 2,4-DCP on Pd/Ti electrode was 93.2% under the conditions of the dechlorination current of 5 mA and dechlorination time of 90 min. The effect of initial 2,4-DCP concentration was also investigated.


2011 ◽  
Vol 689 ◽  
pp. 390-394 ◽  
Author(s):  
Bin Chen ◽  
Da Gang Yin ◽  
Ji Luo ◽  
Quan Yuan ◽  
Jing Hong Fan

Scanning electron microscope (SEM) observation shows that fibula bone is a kind of bioceramic composite consisting of hydroxyapatite layers and protein matters. The hydroxyapatite layers are further composed of hydroxyapatite sheets. The observation also shows that the hydroxyapatite sheets possess quite large volume fraction and also have very long and thin fiber shape. The mechanism of the large volume fraction of the hydroxyapatite sheets to ensure the larger elastic modulus of the bone was investigated based on the model of the bone composite and the theory of the composite mechanics. The investigated result reveals that the large volume fraction of the hydroxyapatite sheets endows the bone with large elastic modulus.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 171 ◽  
Author(s):  
Shashank Ramesh Babu ◽  
Thomas Paul Davis ◽  
Tim Haas ◽  
Antti Jarvenpää ◽  
Jukka Kömi ◽  
...  

As-quenched low-carbon martensitic steels (<0.2 wt.% C) contain auto-tempered carbides. Auto-tempering improves the work hardening and upper-shelf impact energy; however, an efficient characterization method to determine the degree of auto-tempering has not been available. This paper demonstrates an efficient image processing tool that calculates the relative auto-tempered carbide fraction by analyzing scanning electron microscope micrographs. By the process of image segmentation, the qualitative volume fraction of auto-tempered carbides can be determined, and an associated color map produced, which distinguished the levels of auto-tempering. This image processing tool could become useful for the optimization of new low-carbon steel’s mechanical properties.


2017 ◽  
Vol 740 ◽  
pp. 48-53 ◽  
Author(s):  
Rosli Ahmad ◽  
N.R. Shahizan ◽  
M.B.A. Asmael ◽  
Ashraf M.M. Elaswad

The influence of holmium on the microstructure and hardness of Mg-Nd-Gd-Zn-Zr alloys were investigated. Conventional casting methods are used to produce the alloys. All the results were characterized by optical microscopy, scanning electron microscope (SEM) and the Vickers hardness test to highlight the influence of holmium addition. The addition of 2.0 wt.% holmium leads to the combination of rare earth elements which formed Mg-Zn-Nd-Ho phase. The results have shown the addition of Ho improved the microstructure and hardness of Mg-Nd-Gd-Zn-Zr alloys. By adding grain size of 2.0 wt.% holmium had reduced by 18.43%, while the volume fraction increased by 7.34%. The Vickers hardness value improved 6.18% due to the grain refine and volume fraction precipitates. The 2.0 wt.% holmium addition showed a positive result in microstructure and hardness value.


1978 ◽  
Vol 56 (3) ◽  
pp. 288-296 ◽  
Author(s):  
Esther G. McLaughlin ◽  
David J. McLaughlin ◽  
David E. Adson

Developmental anatomy of fruitbodies and mycelium in a clavarioid fungus, Pterula sp. (Aphyllophorales), was studied in the light microscope using plastic-embedded material and in the scanning electron microscope. Differentiation of skeletal and generative hyphae and of the hymenium and sclerotioid patches were similar in the fruitbody and mycelium. Experimental results indicated that the hymenium is ageotropic and that fertile fruitbodies form in both upright and inverted cultures. The nature of the skeletal hyphae, and generic delimitations in the Pterulaceae are discussed.


2007 ◽  
Vol 336-338 ◽  
pp. 763-764
Author(s):  
Wei Bing Ma ◽  
Yan Xia Hao ◽  
Yuan Fang Qu ◽  
Ting Xian Xu

Samples of La(TixMn1-x)O3 (0.1 ≤ x ≤ 0.7) were sintered at different temperatures. The experimental results showed that the resistivity-temperature curves of the samples match NTC characteristic. The crystal structure was analyzed using X-ray diffraction and the microstructure was observed by scanning electron microscope.


2012 ◽  
Vol 531-532 ◽  
pp. 527-530
Author(s):  
Wen Jie Chen ◽  
Bin Jie Xin ◽  
Xiang Ji Wu

Polysulfonamide (PSA) superfine fibers were prepared by the self-developed device using the electrospinning technology. The micro surface morphology of the manufactured PSA fibers was characterized by the Scanning Electron Microscope (SEM). It was found that the diameter of PSA fibers and its variance can be influenced by the electrospinning parameters. The experimental results indicate that the morphology of PSA fibers ranged from irregular (beaded) to uniform structure with an increase of solution concentration; the thickness and its variance of the PSA fibers were decreased with the increasing of applied voltage; the morphology and thickness of the PSA fibers were also affected by the tip-to-collector distance. Our investigation shows that the diameter of the PSA fibers can reach around 100nm when spun at the conditions of 28kv applied voltage, 10wt% solution concentration and 15 cm tip-target distance, with a related homogeneous network distribution.


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