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 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.

Nodular Silicon Al–(12–30)% Si Alloys: Microstructure, Mechanical Properties and Fracture Behaviors

2019 ◽  
Author(s):  
Ruyao Wang ◽  
Wei Hua Lu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Elevated Temperatures ◽  
Primary Silicon ◽  
Silicon Phase ◽  
Applied Loading ◽  
Initiation And Propagation ◽  
Si Content ◽  
Silicon Particles

The microstructure, mechanical properties, and fracture of nodular silicon hypereutectic Al–Si alloys containing 12–30 wt% Si are discussed. The eutectic and primary silicon particles are nodulized, offering an average aspect ratio of 1.60–1.70 with a designed modification practice followed by a solution heat treatment of 8–10 h at 510°C–520°C. Such a soaking temperature does not result in coarsening or clustering of the silicon particles. Nodulization of silicon phase leads to an increase in the tensile strength and ductility of alloys at room and elevated temperatures compared with commercial Al–Si alloys. Increasing the Si content leads the tensile strength and elongation of alloys at room temperature to fall down due to the formation of coarsen primary Si grains, but the ultimate tensile strength at 300°C remains unchanged. The ultimate tensile strength σb-alloy of hypereutectic Al–Si alloys is inversely proportional to square root of maximum silicon size dmax. The initiation and propagation of the crack with continuous increase in applied loading were observed under scanning electron microscope. The fracture surfaces in nodular silicon Al–Si alloys are composed of equiaxed ductile dimples. The finite-element method has been used to study the stress distribution within the different morphologies of Si grain and how Si and Al phases interact during loading.

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.

scholarly journals Al-Si-Re Alloys Cast by the Rapid Solidification Process / Stopy Al-Si-Re Odlewane Metodą Rapid Solidification

2015 ◽  
Vol 60 (4) ◽  
pp. 3057-3062
Author(s):  
M. Szymanek ◽  
B. Augustyn ◽  
D. Kapinos ◽  
J. Żelechowski ◽  
M. Bigaj
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Rapid Solidification ◽  
Structure Refinement ◽  
Diffraction Method ◽  
Solidification Process ◽  
Thin Strip ◽  
X Ray Diffraction ◽  
X Ray ◽  
Casting Technique

The aim of the studies described in this article was to present the effect of rare earth elements on aluminium alloys produced by an unconventional casting technique. The article gives characteristics of the thin strip of Al-Si-RE alloy produced by Rapid Solidification (RS). The effect of rare earth elements on structure refinement, i.e. on the size of near-eutectic crystallites in an aluminium-silicon alloy, was discussed. To determine the size of crystallites, the Scherrer X-ray diffraction method was used. The results presented capture relationships showing the effect of variable casting parameters and chemical composition on microstructure of the examined alloys. Rapid Solidification applied to Al-Si alloys with the addition of mischmetal (Ce, La, Ne, Pr) refines their structure.

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.

Effect of Alternating Traveling Magnetic Field on the Removal of Inclusions from Aluminum Melt

2014 ◽  
Vol 1061-1062 ◽  
pp. 55-60
Author(s):  
Hong Zhang Deng ◽  
Qiu Lin Li ◽  
Ding Guo Yang ◽  
Wei Liu
Keyword(s):  
Magnetic Field ◽  
Solidification Process ◽  
Primary Silicon ◽  
Aluminum Melt ◽  
Agglomeration Effect ◽  
Traveling Magnetic Field ◽  
Silicon Particles

Alternating traveling magnetic field (TMF) was introduced to agglomerate the inclusions with a density smaller than surrounding melt. Primary silicon particles precipitating from the solidification process of hypereutectic Al-Si alloy was regarded as inclusions need removing. Results indicated that alternating TMF was more effective to promote the inclusions to agglomerate into clusters than downward TMF. The effect of alternating TMF to agglomerate the inclusions increases with the increase of current and frequency. There exists the best alternating time to get the best agglomeration effect. In this study, 10s is the best alternating time.

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.

Effect of Compound Modification on Microstructure and Properties of High Silicon Aluminum Alloy

2012 ◽  
Vol 476-478 ◽  
pp. 114-117 ◽  
Author(s):  
Niu Can Liu ◽  
Guang Sheng Kang ◽  
Zhong Xia Liu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Rare Earth ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Unmodified Alloy ◽  
Microstructure And Properties ◽  
Compound Modification ◽  
Double Modification

Double compound modification was carried out for hypereutectic Al-24Si alloy. The experiment showed that double modification with phosphorus and rare earth can fine the microstructure of alloy. The complex modifications of phosphorus and rare earth make the coarse block primary silicon obviously refined and the large needle eutectic silicon modified to the fine fibrous or lamella ones. The alloys with the additions of 0.10% P(phosphorus) and 0.90% RE(rare earth) have the optimal microstructure and the highest mechanical properties. Compared with the unmodified alloy, the primary silicon of alloys can be refined from 93.5μm to 24.1μm. The tensile strength is improved from 248MPa to 305MPa and the elongation is improved from 0.31% to 0.47%. Mechanism of double compound modification with phosphorus and rare earth is discussed as well.

Eutectic Growth Mode of Al-Si Alloy Solidified under High Pressure

2011 ◽  
Vol 130-134 ◽  
pp. 1020-1025
Author(s):  
Li Xin Li ◽  
Ming Li ◽  
Hui Xin Wang ◽  
Zhong Juan Yang
Keyword(s):  
High Pressure ◽  
Electron Microscope ◽  
Eutectic Silicon ◽  
Eutectic Growth ◽  
Normal Pressure ◽  
Growth Mode ◽  
Arc Furnace ◽  
Silicon Phase ◽  
Lamellar Crystal ◽  
Scanning Electron

The Al-Si eutectic alloy solidified under normal pressure was prepared by vacuum Ar-arc furnace. The alloy solidified under high pressure was prepared by hexahedral anvil equipment. The two heavily etched samples were observed by scanning electron microscope. The experiments show that the eutectic silicon phase solidified under high pressure presents curved and near parallel lamellar crystal, and there is definite spacing between the layers, which was very different from that of solidified under normal pressure. So the eutectic growth mode of Al-Si alloy solidified under high pressure was put forward, which indicate that the growth mode of Si have been changed gradually from facet to non-facet under high pressure.

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