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.

Influence of Neodymium on Wear Resistance of Hypereutectic Al-Si Alloy

2015 ◽  
Vol 1095 ◽  
pp. 135-139
Author(s):  
Wei Xi Shi ◽  
Cheng Wu Du ◽  
Gui Mao Li ◽  
Zhi Ming Liu
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Wear Mechanism ◽  
Friction And Wear ◽  
Adhesive Wear ◽  
Primary Silicon ◽  
Oxidative Wear ◽  
Initial Sample ◽  
Unmodified Alloy ◽  
Resistance Tests

The morphology of eutectic and primary silicon phases was analyzed by OM and SEM. OM and SEM results show that pure Nd can significantly refine both eutectic and primary silicon of hypereutectic Al-20%Si alloy. Morphology of primary silicon is transformed from star-shaped and irregular morphology to fine polyhedral and grain size of primary silicon is refined from 80~120 μm to 20~50 μm. Friction and wear resistance tests show that friction coefficient of Al-20%Si alloy reduces after Nd modification. Wear resistance of Al-20%Si alloy after modification is significantly improved as compared to the initial sample. The dominant wear mechanism for 0.3% Nd modified alloy is abrasive wear, adhesive wear and oxidative wear mechanism, but wear mechanism for unmodified alloy is abrasive wear and adhesive wear mechanism.

Influences of Complex Modification of RE and P on the Microstructure and Impact Toughness of Hypereutectic Al-24Si Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1328-1332
Author(s):  
Niu Can Liu ◽  
Hai Dong Li ◽  
Zhong Xia Liu
Keyword(s):  
Impact Toughness ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Initiation Energy ◽  
Unmodified Alloy ◽  
Average Size ◽  
The Impact

The influences of RE and P complex modification on microstructure and impact toughness of hypereutectic Al-24Si alloy are investigated. The result shows that the coarse block primary silicon is refined obviously and its edges and angles are blunted under the influences of the complex modification of RE and P. The large needle eutectic silicon is modified to the short-rod or particle ones also. The alloys have the finest microstructure and highest impact toughness when adding about 0.10% P and 0.9% RE into alloys. Compared with the unmodified alloy, the average size of primary silicon in the modified alloys refined from 93.5μm to 24.1μm and the impact toughness of alloys increases to 11.0062J/cm2 from 7.3572J/cm2. The excellent impact toughness of alloys can be attributed to the increase of initiation energy and expand energy of the cracks caused by the refinement of primary silicon and eutectic silicon after complex modified with P and RE.

Semisolid Casting of Hypereutectic Al-Si-Cu Alloy with Sono-Solidified Slurry

2014 ◽  
Vol 622-623 ◽  
pp. 804-810 ◽  
Author(s):  
Yoshiki Tsunekawa ◽  
Shinpei Suetsugu ◽  
Masahiro Okumiya ◽  
Yuichi Furukawa ◽  
Naoki Nishukawa ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Eutectic Temperature ◽  
High Strength ◽  
Primary Silicon ◽  
Optical Microscope ◽  
Eutectic Region ◽  
Hetero Structure ◽  
Cu Alloys ◽  
Strength And Ductility ◽  
Silicon Particles

Hypereutectic Al-Si-Cu alloys which are typical light-weight wear-resistant materials, are required to improve the ductility as well as the strength and wear-resistance for the wider applications. Increase in amounts of primary silicon particles causes the modified wear-resistance of hypereutectic Al-Si-Cu alloys, however, it leads to the poor strength and ductility. It is known that dual phase steels composed of hetero-structure have succeeded to bring contradictory mechanical properties of high strength and ductility concurrently. In order to apply the idea of hetero-structure to hypereutectic Al-Si-Cu alloys for the achievement of high strength and ductility along with wear resistance, ultrasonic irradiation to molten metal during the solidification, which is named sono-solidification, was carried out from its molten state to just above the eutectic temperature. The sono-solidified Al-17Si-4Cu alloy is composed of hetero-structure, that is, hard primary silicon particles, soft non-equilibrium α-Al phase and eutectic region. Rheocasting was performed at just above the eutectic temperature with sono-solidified slurry to shape a disk specimen. After the rheocasting with modified sono-solidified slurry held for 45s at 570oC, the quantitative optical microscope observation exhibits that the microstructure is composed of 18area% of hard primary silicon particles and 57area% of soft α-Al phase, in contrast there exist only 5area% of primary silicon particles and no α-Al phase rheocast with normally solidified slurry. Hence the tensile tests of T6 treated rheocast specimens with modified sono-solidified slurry exhibit the improved strength and 5% of elongation, regardless of more than 3 times higher amounts of primary silicon particles compared to that rheocast with normally solidified slurry.

scholarly journals The Big Chill

2000 ◽  
Vol 122 (11) ◽  
pp. 94-97 ◽  
Author(s):  
John DeGaspari
Keyword(s):  
Weight Loss ◽  
Wear Resistance ◽  
Machine Tools ◽  
Heat Treating ◽  
Martensitic Phase ◽  
Treated Steel ◽  
Steel Grades ◽  
Quenched Steel ◽  
Improve Wear Resistance ◽  
Wear Tests

This article reviews the improvement of wear resistance of steel that can amount to found money, particularly in industrial uses such as stamping dies and machine tools. Quenching converts most of the austenitic microstructure to the martensitic phase, which is finer and denser. Martensite, the chief component of quenched steel, consists of hardened carbides that provide the higher hardness and wear resistance. Cryogenics has attracted the interest of others who want to improve wear resistance in wider applications. As a follow-on treatment to conventional heat treating, cryogenics should be seen as the very last step in the process. After wear tests, in which cryogenically treated parts were run against an abrasion wheel, it was found that weight loss on several steel grades improved by factors of two to five. It was also found that the overall hardness of the treated steel did not change noticeably.

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.

Influence of Si Content on Microstructure and Erosion Properties of Al-Based Alloy

2014 ◽  
Vol 960-961 ◽  
pp. 109-112
Author(s):  
Xiao Ming Wang ◽  
Sheng Zhu ◽  
Jian Zhong Cui ◽  
Qing Chang ◽  
Qing Feng Zhu
Keyword(s):  
Magnesium Alloy ◽  
Chemical Elements ◽  
Eutectic Silicon ◽  
Testing Machine ◽  
Theoretical Principle ◽  
Primary Crystal ◽  
Silicon Phase ◽  
Crystal Silicon ◽  
Erosion Properties ◽  
Si Content

In order to develop new protective materials for magnesium alloy, Al-based alloys with different Si-content were fabricated by copper mold casting. Microstructure, erosion properties of the ingot samples were characterized or tested by using spectrum analysis, optical imcroscope, salt testing machine etc, respectively. The results indicated that the microstructure of Al-1.9Si-1.32Mg-0.40Mn was mostly dendritic crystal. That of Al-13Si consisted of α-Al, flaky eutectic silicon and primary crystal silicon. That of Al-18Si-0.01%P was consistent of a large proporation of primary crystal silicon phase, a part of eutectic silicon phase and a little of α-Al phase. With Si-content increasing, anti-corrosion properties of Al-based alloy gradually improved, which could provide theoretical principle to determine chemical elements of protective materials for magnesium alloy.

Effect of Heat Treatment on Microstructure, Hardness and Wear of Aluminum Alloy 332

2015 ◽  
Vol 786 ◽  
pp. 18-22 ◽  
Author(s):  
Fizam Zainon ◽  
Khairel Rafezi Ahmad ◽  
Ruslizam Daud
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Aluminum Alloy ◽  
Room Temperature ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Room Temperature Aging ◽  
Temperature Aging ◽  
Silicon Particles

This paper describes a study on the effects of heat treatment on the microstructure, hardness and wear of aluminum alloys 332 (AlSi9Cu3Mg). The solution treatment was performed at 500°C for 5 hours and then quenched in water at room temperature. Aging was performed at 170°C for 2 hours. The findings revealed that after a full heat treatment, the structure of the eutectic silicon formed toward fragmentation and spheroidization, and the silicon particles became coarse (look-like rounded). Hard intermetallic compound (Mg2Si) appeared on the microstructure after the aging treatment completed. Compared to the as-cast, the hardness of the alloys has improved to 44.84%, and the wear rate of the solution treatment had decreased to 26% while the aging treatment showed a deterioration of 79.42%. The study concludes that aging treatment improves the hardness of AA332 alloys and enhanced the wear resistance of the substance.

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.

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.

Effects of Mixing Melt Treatment and Heat-Treatment on the Microstructure and Wear Resistance of Al-22%Si Alloys

2013 ◽  
Vol 815 ◽  
pp. 195-200 ◽  
Author(s):  
Yuan Dong Li ◽  
Ming Tao He ◽  
Shao Hua Hu ◽  
Jiang Long Suo ◽  
Ying Ma
Keyword(s):  
Heat Treatment ◽  
Wear Mechanism ◽  
Adhesive Wear ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Wear Rates ◽  
Controlled Diffusion ◽  
Liquid Mixing ◽  
Heat Treated ◽  
Worn Surface

The effect of hypereutectic Al-22%Si alloys prepared by means of Controlled Diffusion Solidification (CDS) followed by subsequent heat-treatment on the microstructure and sliding abrasive wear behaviors is investigated. The results show that the primary silicon morphology, size and distribution can be improved by CDS, especially for the case of liquid-liquid mixing. After heat-treatment, the eutectic silicon can be spheroidized. Under the same load, the wear rates for the identically mixed and heat-treated Al-22%Si alloys are lower than those unheat-treatment, and the wear rate of liquid-liquid mixed and heat-treated Al-22%Si alloy reach its minimum. The wear mechanism of traditional cast Al-22%Si alloy includes adhesive wear and fatigue breaking-off, while the liquid-liquid mixing can effectively restrain flaking on the worn surface and avoid the fatigue breaking-off, the wear mechanism is changed into abrasion wear.

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