scholarly journals Effect of Rare Earth on Microstructure and Wear Resistance of In-Situ-Synthesized Mo2FeB2 Ceramics-Reinforced Fe-Based Cladding

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3633
Author(s):  
Jun Jin ◽  
Junsheng Sun ◽  
Weimin Wang ◽  
Jijun Song ◽  
Hu Xu
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Rare Earth ◽  
Phase Composition ◽  
Sintered Sample ◽  
Area Fraction ◽  
Grain Refining ◽  
Grain Sizes ◽  
Carbon Arc

Mo2FeB2 ceramics-reinforced Fe-based cladding with various rare earth (RE) concentrations were prepared by the carbon arc surfacing process. The effects of RE content on the microstructure, phase composition, hardness and wear resistance of the cladding were systematically discussed. Meanwhile, the area fraction and grain size of Mo2FeB2 phase were exactly measured. Moreover, the refining mechanism of rare earth Y was analyzed. Results revealed that the claddings consisted of Mo2FeB2, FeCr, MoB and CrB. Adding the rare-earth Y decreased the grain sizes of Mo2FeB2 phase. Furthermore, grain-refining effects of Mo2FeB2 phase were significant when the RE content was 2% and hard phases evenly distributed in the cladding. In addition, the maximum microhardness value of claddings was about 1078 HV. The claddings with 2% RE contents had better wear resistance, which was equivalent to a sintered sample.

Investigation of mechanical and tribological properties of different grain size iron scale reinforced polymer composite

2020 ◽  
pp. 096739112098276
Author(s):  
Bilal Kursuncu ◽  
Azmi Erdogan ◽  
M Sabri Gok ◽  
Bilal Demirel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Polymer Material ◽  
Wear Mechanism ◽  
Steel Production ◽  
Production Plant ◽  
Grain Sizes ◽  
Iron Scale

In this study, the change of mechanical properties by adding iron scales of different sizes into polypropylene (PP) was investigated. The iron scale was obtained from a steel production plant and adjusted to 30, 50, 90, 120, and 150 µm grain sizes. These iron scales were then added to the polymer material at a rate of 5% by weight. Wear and tensile strength tests were applied to the samples, which were formed in two different types. According to the results obtained, the wear and tensile strength of polymer material in all grain sizes were improved with an added iron scale. It was observed that the wear resistance of the composite material formed with the addition of fine-grained reinforcing element was the highest. Although grain size increased with increasing tensile strength, wear resistance did not increase. Besides, the friction coefficient was measured to be lower at increasing load. While the effective wear mechanism in pure polymer material is plastic deformation, this wear mechanism has not been found in composite materials with different grain sizes. In this study, it has been shown that iron scales have a positive effect on the mechanical properties of polymer composites.

In Situ Observation of Grain Growth and Recrystallization of Steel at High Temperature

2010 ◽  
Vol 638-642 ◽  
pp. 1077-1082 ◽  
Author(s):  
Yasuhiro Yogo ◽  
Kouji Tanaka ◽  
Koukichi Nakanishi
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Grain Growth ◽  
In Situ Observation ◽  
Initial Structure ◽  
Grain Sizes ◽  
Dynamic Observation ◽  
Average Grain Size ◽  
Observation Method

An in-situ observation method for structures at high temperature is developed. The new observation device can reveal grain boundaries at high temperature and enables dynamic observation of these boundaries. Grain growth while maintaining microstructure at high temperature is observed by the new observation device with only one specimen for the entire observation, and grain sizes are quantified. The quantifying process reveals two advantages particular to the use of the new observation device: (1) the ability to quantify grain sizes of specified sizes and (2) the results of average grain size for many grains have significantly less errors because the initial structure is the same for the entire observation and the quantifying process. The new observation device has the function to deform a specimen while observing structures at high temperature, so that enables it to observe dynamic recrystallization of steel. The possibility to observe recrystallization is also shown.

LaF3 Influences on Wear Resistance of TiC/Ni Cladding Layer by Laser Cladding In Situ Fabricated

2012 ◽  
Vol 549 ◽  
pp. 335-339 ◽  
Author(s):  
Cheng Qiang Wang ◽  
Li Juan Wang ◽  
Jiang Qiao Wu ◽  
Zi Zhen Chen ◽  
Yong Jun Niu
Keyword(s):  
Wear Resistance ◽  
Rare Earth ◽  
Laser Cladding ◽  
Friction And Wear ◽  
In Situ Synthesis ◽  
Particle Segregation ◽  
Cladding Layer ◽  
Tic Particle ◽  
Heterogeneous Phase

The TiC/Ni composite coating was prepared by Laser Cladding In-situ Synthesis on the surface of damper plate with Ni--Ti-Mo-C -LaF3 powder．Microstructure and Wear resistance have been studied throughout EPMA、SEM and M—2000 Friction and Wear Tester．It was found that the microstructure got more homogenized grain fineness became finer, TiC distributed better and heterogeneous phase decreased, as adding moderate rare earth LaF3. When the content of LaF3 was 1%, the highest microhardness was got. While the optimal wear resistance properties were obtained with 2% LaF3. The laser cladding with excessive LaF3 has more TiC particle segregation which induces hardness and wear resistance of cladding layer.

scholarly journals Locally Reinforcement TiC-Fe Type Produced in Situ in Castings

2016 ◽  
Vol 16 (3) ◽  
pp. 77-82 ◽  
Author(s):  
E. Olejnik ◽  
Ł. Szymański ◽  
P. Kurtyka ◽  
T. Tokarski ◽  
W. Maziarz ◽  
...  
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Raw Materials ◽  
Cast Steel ◽  
Structural Elements ◽  
Wear Resistant ◽  
Mineral Raw Materials ◽  
Energy Consuming ◽  
The Subject

Abstract Refinement is one of the most energy consuming technological process, aimed at obtaining mineral raw materials of the proper grain size. Cast structural elements such as jaws or hammers in crushing machines operate under conditions of an intensive wear. The data indicate that 80 % of failures of machines and devices is caused by wearing of rubbing surfaces. This problem became the subject of several scientific and industrial investigations carried out in the whole world in order to produce materials ultra- wear resistant. Methods allowing to obtain wear resistant composite castings are discussed in the hereby paper. Within the performed research microstructures of the produced composite zones were presented and the comparative analysis with regard to mechanical and functional properties of local composite reinforcements in relation to the commercial alloys of increased wear resistance was performed. The results show almost twenty five times increase in wear resistance compared to manganese cast steel containing 18 % Mn.

scholarly journals Applications of Rare Earth Metals in Al-Si Cast Alloys

2021 ◽  
Author(s):  
Mohamed Gamal Mahmoud ◽  
Yasser Zedan ◽  
Agnes-Marie Samuel ◽  
Victor Songmene ◽  
Herebert W. Doty ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Rare Earth ◽  
High Purity ◽  
Eutectic Silicon ◽  
Rare Earth Metals ◽  
Grain Refining ◽  
Cast Alloys ◽  
Noticeable Reduction ◽  
The Cost

The present article reviews a large number of research publications on the effect of mischmetal (MM), rare earth metals (RE), La or Ce, and combinations of La + Ce on the performance of Al-Si cast alloys mainly 319, 356, 380, 413, and 390 alloys. Most of these articles focused on the use of rare earth metals as a substitute for strontium (Sr) as a eutectic silicon (Si) modifier if added in low percentage (< 1 wt.%) to avoid precipitation of a significant amount of insoluble intermetallics and hence poor mechanical properties. Other points that were considered were the affinity of RE to react with Sr., reducing its effectiveness as modifier, as well as the grain refining efficiency of the added RE in any form. None of these articles mentioned the exact composition of the RE used and percentage of tramp elements inherited from the parent ore. Using high purity La or Ce proved to have no effect on the Si shape, size or distribution, in particular at low solidification rates (thick sections). However, regardless the source of the RE, its addition to Sr-modified alloys reduced the modification effect. As for grain refining, apparently a high percentage of RE (> 1 wt.%) is required to achieve a noticeable reduction in grain size, however at the cost of alloy brittleness.

Recrystallization and Roping in a 6000 Series Al Alloy

2012 ◽  
Vol 715-716 ◽  
pp. 685-689
Author(s):  
Tricia A. Bennett ◽  
Roumen H. Petrov ◽  
Leo Kestens
Keyword(s):  
Grain Size ◽  
Area Fraction ◽  
Al Alloy ◽  
Microstructural Characteristics ◽  
Grain Sizes ◽  
Recrystallized Grain Size

Recrystallization was investigated in the context of its effect on the roping phenomenon in a 6000 series Al alloy. The findings suggest that, in general, the recrystallized grain size affects the material's susceptibility to roping more than the actual area fraction of specific texture components. For example, bands of Cube grains were typically observed in the final processed samples in cases which had coarse, recrystallized grain sizes from the earlier stages of processing. In contrast, bands were not observed for cases having fine, intermediate recrystallized grain sizes. Although microstructure and texture are highly intertwined, these findings suggest that the microstructural characteristics, such as the recrystallized grain size, are more important than those related to the texture.

scholarly journals Grain Size Distribution and Clay Mineral Distinction of Rare Earth Ore through Different Methods

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 353 ◽  
Author(s):  
Lingkang Chen ◽  
Xiongwei Jin ◽  
Haixia Chen ◽  
Zhengwei He ◽  
Lanrong Qiu ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Solution Concentration ◽  
Low Ph ◽  
Low Grade ◽  
Leaching Rate ◽  
Leaching Solution

Although clay mineral content in ion-absorbed rare earth ores is crucial for migrating and releasing rare earth elements, the formation, distribution, and migration of clay minerals in supergene rare earth ores have not been fully understood. Therefore, this study analyzes the characteristics of clay mineral type and content, soil particle size, pH value, leaching solution concentration, and leaching rate. This analysis was performed using different methods, such as regional rare earth mine soil surveys, in situ leaching profile monitoring, and indoor simulated leaching. The results showed that the grain size and volume curve of rare earth ore have unimodal and bimodal shapes, respectively. X-ray diffraction showed the differences in clay mineral types formed by different weathered bedrocks. The principal clay minerals were kaolinite, illite, chlorite, and vermiculite, with their relative abundance varying with parent rock lithology (granite and low-grade metamorphic rocks). In the Ganxian granite weathering profile, the kaolinite content increased from top to bottom. The decomposition of feldspar minerals to kaolinite was enhanced with an increase in the SiO2 content during weathering. The in situ leaching profile analysis showed that the kaolinite content increased initially and then decreased, whereas the illite/mica content exhibited the opposite trend. Under stable leaching solution concentration and leaching rate, clay mineral formation is favored by lower pH. Low pH, low leaching rate, and highly-concentrated leaching solution (12 wt%) resulted in a slow increase in kaolinite content in the upper part of the profile (30 cm). A lower concentration of the leaching solution (4 wt%) resulted in rapid enrichment of kaolinite after 15 days. Low pH, leaching solution concentration, and leaching rate promoted the formation of distinct kaolinite horizons. We suggest that by disregarding other control factors, rare earth recovery of over 90% can be achieved through leach mining with solutions of 8 wt% and a pH of 5 at a leaching rate of 5 mL/min.

Preferential Orientation of Photochromic Gadolinium Oxyhydrides

2020 ◽  
Author(s):  
Elbruz Murat Baba ◽  
Jose Montero ◽  
Dmitrii Moldarev ◽  
Marcos V. Moro ◽  
Max Wolff ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Rare Earth ◽  
Preferential Orientation ◽  
Reactive Magnetron ◽  
Flow Ratio ◽  
Deposition Pressure ◽  
Step Process ◽  
Oxidation In Air ◽  
Key Parameter

<p>We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH<sub>2-x</sub>) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations, and photochromic response of the films are strongly dependent on the deposition pressure. GdHO films show preferential orientation along the [100] direction and exhibit photochromism when synthesized at deposition pressures up to 5.8 Pa and. The photochromic contrast is larger than 20 % when the films are deposited below 2.8 Pa with 0.22 H<sub>2</sub>/Ar flow ratio. We argue that the degree of preferential orientation defines the oxygen concentration which is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above are explained by the oxidation-induced decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas. </p>

Phase composition of modern microcrystalline modifiers containing silicon, alkaline earth and rare earth metals

2020 ◽  
pp. 25-34
Author(s):  
V. P. Ermakova ◽  
◽  
S. Yu. Melchakov ◽  
V. G. Smirnova ◽  
L. A. Ovchinnikova ◽  
...  
Keyword(s):  
Rare Earth ◽  
Phase Composition ◽  
Alkaline Earth ◽  
Rare Earth Metals
Sign in / Sign up

Export Citation Format

Share Document