scholarly journals Effect of Rare Earth Upon As-Cast Microstructure and High Temperature Performance of ZA40 Alloy

2014 ◽  
Vol 8 (1) ◽  
pp. 251-256
Author(s):  
Jiaming Ji ◽  
Guocui Meng ◽  
Yuanyong Lu ◽  
Honghong Shao ◽  
Dongqing Gu
Keyword(s):  
Wear Resistance ◽  
Rare Earth ◽  
High Temperature ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Silicon Phase ◽  
Different Temperatures ◽  
Properties Of Materials ◽  
Re Elements ◽  
Cast Microstructure

In testing comparison, this study is made on the modification effect of 0.05 wt.% La-rich rare earth (RE) upon as-cast microstructure, mechanical properties of materials at high temperatures (100, 150, 200°C) and wear resistance under different temperatures (100and 200°C) of ZA40 alloy containing Si. The addition of RE shows that it can not only effectively refine Al-rich and Cu-rich phase, but also reduce the amount of needle-like eutectic silicon, and then make the size of massive primary silicon phase smaller. Thus, there are the improvement of strength, ductility and wear resistance of materials at high temperature. The analyses are also conducted on the mechanism of underlying RE elements.

Effects of the Morphology of Silicon Phase on the Properties of Zinc Based Composites

2007 ◽  
Vol 561-565 ◽  
pp. 693-696
Author(s):  
Ai Li Wei ◽  
Wei Song ◽  
Xiao Dong Wu ◽  
Wei Liang ◽  
Li Hua Xu
Keyword(s):  
Rare Earth ◽  
Sodium Salt ◽  
Eutectic Silicon ◽  
Silicon Crystal ◽  
Wear Test ◽  
Matrix Alloy ◽  
Primary Silicon ◽  
Test Material ◽  
Silicon Phase ◽  
Pure Zinc

This paper deals with the microstructure and property of zinc based composites ZA27Six under the treatment of the sodium salt and the rare earth. The test material was prepared with pure zinc ingot (Zn≥99.99wt %) and the Al-Si matrix alloy. Basic composition of the test sample was Al (25~30 wt %), Si (2.5~6.0 wt %) and Zn for the rest. Impact toughness test, tensile test and wear test were conducted. The test results show that under the treatment of sodium the massive primary silicon crystal can transform to nodular silicon on which eutectic silicon crystal can form and grow in rod-like. It is also found that the combined effect of rare earth and sodium salt can obviously refine the silicon phase and the zinc based composites enhanced by nodular silicon has better hardness and wear- resistance.

On the Modification of Hypereutectic Al-15Si Alloy Using Rare Earth Ce

2013 ◽  
Vol 467 ◽  
pp. 16-19 ◽  
Author(s):  
Mehdi Shafei ◽  
Najmadin Arab ◽  
Karim Zangeneh Madar
Keyword(s):  
Rare Earth ◽  
Eutectic Silicon ◽  
Solidification Process ◽  
Primary Silicon ◽  
Negative Influence ◽  
Silicon Phase ◽  
Casting Technique ◽  
Scanning Electron ◽  
Silicon Particles ◽  
Conventional Light Microscope

Hypereutectic Al-15Si (wt pct) alloys with various content of rare earth Ce were prepared by conventional casting technique. The influence of the primary silicon phase and eutectic silicon on the solidification process of hypereutectic Al-15Si alloys with the addition of Ce is presented. The microstructures were examined with conventional light microscope and scanning electron microscope. The simultaneous refinement of both the primary and the eutectic silicon particles wasntachieved with Ce additions. The results showed that the addition of cerium doesnt cause to refinement of the primary silicon grains, while cerium is caused to stress on concentration regions.The results showed that the addingthe cerium had a negative influence on the alloys tensile strength.

scholarly journals Research on Microstructure and Growth Mechanism of Different Primary Silicon in Hypereutectic Aluminum Alloy

2022 ◽  
Vol 2152 (1) ◽  
pp. 012022
Author(s):  
Gaozhan Zhao ◽  
Zhihui Xing ◽  
Ming Li ◽  
Shiqing Gao ◽  
Jianquan Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Growth Mechanism ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Phase Growth ◽  
Silicon Phase ◽  
Tetrahedral Crystal ◽  
Impurity Elements ◽  
Growth Methods ◽  
Cast Microstructure

Abstract The as-cast microstructure of a typical hypereutectic Al-25Si alloy was studied, and the growth mechanism of different primary silicon phases was analyzed. The results show that the as-cast microstructure phase composition of the alloy is mainly primary silicon and eutectic silicon. Primary silicon is mainly petal-like, massive and other complex polyhedrons, and there are a lot of cavities, cracks and other defects in the interior and boundary; Eutectic silicon is coarse and long needle-like, and the distribution is relatively messy, which seriously deteriorates the mechanical properties and cutting performance, and hinders the further application of the alloy in the field of lightweight pistons. Petal-shaped primary silicon is grown by combining five tetrahedral crystal nuclei in the melt into a decahedron, while bulk primary silicon is mainly caused by the unbalanced aggregation of impurity elements. And these two types of silicon phase growth methods are related to the twin groove growth mechanism, which is the result of a combination of multiple mechanisms.

Methodology for Measurement of Density of Liquid Oxides

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Jan Hrbek ◽  
Bence Mészáros ◽  
Mykhaylo Paukov ◽  
Martin Kudláč
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Extreme Conditions ◽  
Nuclear Accidents ◽  
System A ◽  
Different Temperatures ◽  
Density Values ◽  
Properties Of Materials ◽  
The Difference

Abstract Measurement of physical properties of materials in extreme conditions, such as high temperature, is limited by technological challenges. Nevertheless, modeling of several phenomena relies on the existence of experimental data for their validation. In this study, a method suitable for determination of density in a liquid phase at high temperature is proposed and tested on Al2O3–ZrO2 system. A methodology for acquiring the temperature dependence of density for radioactive materials is proposed and is aimed to refine severe nuclear accidents modeling. The oxide was melted in an induction furnace with a cold crucible. The measurement was based on evaluation of the volume of the melt at different temperatures, in a range from 2100 to 2400 °C. The densities of the oxide in the solid-state and the skull-layer were measured using a pycnometer. A temperature dependence of the density was established and the results were compared with literature. The difference between existing data and the measured values in this work was less than 5%. Thus, the proposed methodology provides reliable density values in extreme conditions.

Mechanical Properties Analysis of Super Early-Strength Composite Fiber Concrete after High Temperature

2014 ◽  
Vol 584-586 ◽  
pp. 1351-1354
Author(s):  
Chang Zheng Sun ◽  
Rui Xiao Wu ◽  
Hai Nan Zhao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Concrete Specimen ◽  
Composite Fiber ◽  
High Temperature Mechanical Properties ◽  
Fiber Concrete ◽  
Different Temperatures ◽  
Axial Compressive Strength ◽  
Properties Of Materials ◽  
Early Strength

Experimental method is applied to analysis the mechanical properties of super early-strength composite fiber concrete on high temperature. Specimen are heated to in the stove at different temperatures for 30 Minutes, then the axial compressive strength can be measured. The experimental results showed that: the high temperature mechanical properties of materials decreased significantly; compared to ordinary concrete specimen, the mechanical properties of super early-strength composite fiber concrete decline slower.

High Temperature Wear Resistance of Cobalt-Based Cladding Layer Surfacing on H13 Steel

2019 ◽  
Vol 815 ◽  
pp. 81-88
Author(s):  
Zi Li Zhou ◽  
Wu Hua Yuan ◽  
Tie Hui Fang ◽  
Qiang Fu
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Oxide Layer ◽  
Wear Surface ◽  
Wear Test ◽  
H13 Steel ◽  
High Temperature Wear ◽  
Cladding Layer ◽  
300M Steel ◽  
Different Temperatures

In order to improve the wear resistance of H13 steel, a layer of cobalt-based cladding layer was deposited on the surface of H13 steel by plasma transfer arc welding technology. High-temperature wear test was carried out on H13 steel and cladding layer under 300N loading force, and the two materials were ground at different temperatures with 300M steel. The experimental results show that under 300N loading force, the wear resistance of the cladding layer and H13 steel decreases first and then increases with the increase of temperature, which is related to the softening and oxidation of the material. At 350°C,the material softens and the oxide layer fails to entirely cover the wear surface, so the wear resistance of the cladding layer and H13 steel is lowered. At 500°C and 650°C, the wear surface is covered by a dense oxide layer, which protects the surface of the material from direct wear. The higher the temperature is, the thicker the oxide layer is and the better the protection effect is. At various experimental temperature, the wear resistance of the cladding layer is better than that of H13 steel. The surfacing of a cobalt-based cladding layer on the surface of H13 can improve the wear resistance of H13 steel.

Study of the Boron Distribution and Microstructure of Solidified Al-Si Alloy During the Process of Silicon Purification

2018 ◽  
Vol 37 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Yanlei Li ◽  
Jian Chen ◽  
Songyuan Dai
Keyword(s):  
Cooling Rate ◽  
Transition Layer ◽  
Boron Content ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Silicon Phase ◽  
Cooling Rates ◽  
Average Width ◽  
Boron Distribution ◽  
Silicon Purification

AbstractThe Al-Si melts that contain different silicon contents were solidified with a series of cooling rates, and the boron contents in primary silicon phases and eutectic silicon phases were measured and discussed. The results indicate that the boron content in the eutectic silicon phases is higher than that in the primary silicon phases when the cooling rate is constant. When the cooling rate decreases, the boron content in the primary silicon phases decreases, but the boron content in the eutectic silicon phases increases. The microstructure observations of solidified ingots show that there is an interface transition layer beside the primary silicon phase, and the average width of the interface transition layer increases with decreasing cooling rate.

Influences of Complex Modification of RE and P on the Wear Resistance of Hypereutectic Al-24Si Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1647-1650
Author(s):  
Niu Can Liu ◽  
Jun Qing Li ◽  
Hai Dong Li
Keyword(s):  
Weight Loss ◽  
Wear Resistance ◽  
Wear Mechanism ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Primary Crystal ◽  
Crystal Silicon ◽  
Unmodified Alloy ◽  
Improve Wear Resistance ◽  
Silicon Particles

The influences of RE and P complex modifications on microstructures and wear-resistance of hypereutectic Al-24Si alloy were studied. The results show that the complex modifications of P and RE make the coarse block primary crystal silicon refined and their edges and angles are passivated, the large needle-like network eutectic silicon be modified to the fine lamella or particle ones. The optimum modification effect occurs with 0.10%P and 0.9%RE. The complex modification of P and RE can also obviously improve wear resistance of hypereutectic Al-24Si alloy. When the tested alloys modified with 0.10%P and 0.9%RE, the optimal wear resistance of modified alloys is obtained. The weight loss is decreased to 3.9mg from 5.4mg of the unmodified alloy, decreased by 27.8%. The abrasive wear caused by the breaking of Si phase is dominant wear mechanism of the alloy. It can be attributed to the refinement of primary silicon and eutectic silicon particles and the increase of strength and ductibility of alloys caused by the complex modification of P and RE.

The Possibility of Production of Cemented Carbide under High Pressure and High Temperature

2012 ◽  
Vol 727-728 ◽  
pp. 380-385
Author(s):  
C.M.F.G. Marques ◽  
G.S. Bobrovnitchii ◽  
J.N.F. Holanda
Keyword(s):  
High Pressure ◽  
Wear Resistance ◽  
Rare Earth ◽  
High Temperature ◽  
Earth Element ◽  
Cemented Carbide ◽  
Carbide Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Technical Properties

In this work the possibility of production of cemented carbide doped with rare-earth element (Y2O3) under condition of high pressure and high temperature (HPHT) was investigated. Initially, the cemented carbide powder (WC10wt.%Co) was submitted to conventional pressing at 800 MPa. The compacts were then sintered at 1400 °C for 40 s under a pressure of 5.5 GPa. The cemented carbide pieces were characterized in terms of relative density, coercive force, mechanical strength, microhardness, and wear resistance. The phase analysis was done by X-ray diffraction. It was established promising results on the production of cemented carbide under high pressure. Moreover, the addition of up to 1.5 wt.% of yttrium oxide in relation the cobalt phase enhanced the technical properties of the cemented carbide.

scholarly journals Impurity Distribution after Solidification of Hypereutectic Al-Si Melts and Eutectic Al-Si Melt

2019 ◽  
Vol 38 (2019) ◽  
pp. 389-395 ◽  
Author(s):  
Yanlei Li ◽  
Jian Chen ◽  
Songyuan Dai
Keyword(s):  
Eutectic Silicon ◽  
Mass Conservation ◽  
Primary Silicon ◽  
Impurity Distribution ◽  
Icp Oes ◽  
Silicon Phase ◽  
Solvent Refining ◽  
Aluminum Phase

AbstractHypereutectic Al-Si melts and eutectic Al-Si melt were solidified to study boron and phosphorus distributions in primary silicon phase, eutectic silicon phase and eutectic aluminum phase during Al-Si solvent refining. The boron and phosphorus contents in the primary silicon phase and the eutectic silicon phase were determined by ICP-OES, and the boron and phosphorus contents in the eutectic aluminum phase were calculated by the principle of mass conservation. The primary silicon phase has lowest boron and phosphorus contents, while the eutectic aluminum phase has highest boron and phosphorus contents.

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