Fabrication and hardness investigation of Al-15%Mg2Si-3%Cu in-situ cast composite

Abstract This study was undertaken with the aim of modifying the microstructure and improving the tribological properties of in situ Al-20Mg2Si composite. For this purpose, friction stir processing (FSP) was applied on the composite at constant travel and rotation speeds of 110 mm/min and 1500 rpm, respectively, using three different tool pin profiles: threaded tapered cylindrical, triangular tapered, and triangular threaded tapered. The sliding wear tests were conducted using a pin-on-disc apparatus under the applied load of 30 N and sliding distance of 1000 m at room temperature. The results showed that FSP substantially improved tribological properties of the as-cast composite. The best result was observed in the sample processed by the threaded triangular tapered tool, where compared with the as-cast composite, its wear rate and average friction coefficient decreased by almost 40% and 18%, respectively. This improvement can be attributed to the significant refinement and uniform redistribution of Mg2Si intermetallics, especially the coarse irregular-shaped primary crystals, the formation of ultrafine grains, and elimination of casting defects from the substrate microstructure of the processed sample, which improves its hardness and increased its potential in supporting the oxide tribolayer on the composite surface.

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Microstructure and Tensile Properties of 1-D Forged (TiB+TiC)/Ti Composite

Materials Science Forum ◽

10.4028/www.scientific.net/msf.747-748.926 ◽

2013 ◽

Vol 747-748 ◽

pp. 926-931 ◽

Cited By ~ 1

Author(s):

Chang Jiang Zhang ◽

Fan Tao Kong ◽

Shu Long Xiao ◽

Li Juan Xu ◽

Yuong Chen ◽

...

Keyword(s):

High Temperature ◽

Aspect Ratio ◽

Grain Boundaries ◽

Tensile Properties ◽

Room Temperature ◽

Fracture Mechanisms ◽

Cast Composite ◽

Temperature Fracture ◽

Cast Microstructure

In this work, 2.5vol. % (TiB+TiC)/Ti composite was prepared by in situ casting route then 1-D forging. The microstructure and tensile properties were presented and discussed. The results indicate that the as cast microstructure can be significantly modified by 1-D forging. After forging, TiB and TiC segregated at the prior β grain boundaries within the as-cast composite tend to fracture and align perpendicular to forging direction. Reduction in aspect ratio of reinforcements and α lath is also observed. 1-D forging can enhance the strength and elongation of as cast composite significantly. However, the increment in strength is quite limited as strain temperature increases to 700 °C. Additionally, room temperature and high temperature fracture mechanisms are also discussed.

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Effect of Isothermal Reheating at Different Holding Times on The Microstructure of Al-Mg[sub 2]Si In-situ Cast Composite

10.1063/1.3457619 ◽

2010 ◽

Author(s):

A. Malekan ◽

M. Emamy ◽

J. Ghiasinejad ◽

M. R. Ghorbani ◽

F. Barlat ◽

...

Keyword(s):

Cast Composite

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Effect of Heating Temperature of Quenching on the Properties of TiCp/Fe Composite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.152-153.330 ◽

2010 ◽

Vol 152-153 ◽

pp. 330-335

Author(s):

Shi Jie Fang ◽

Qiao Han ◽

Yu Qian Zhao ◽

Chun He Zang

Keyword(s):

Wear Resistance ◽

Heating Temperature ◽

Steel Matrix ◽

Cast Composite ◽

Light Load ◽

Tic Particle ◽

Optimum Heating ◽

In Situ Tic ◽

Improve Wear Resistance

In-situ TiC particle reinforced iron based composite was further processed using quenching, and the effect of heating temperature of quenching for the properties of TiCp/Fe composite was investigated. The quenching phases of the composite are as same as that of the as-cast composite. Quenching can further improve wear resistance of TiCp/Fe, and the composite via quenching route is more suitable for the application of light load. When the optimum heating temperature of quenching of TiCp/Fe is equal to 780 °C, the microstructure of the steel matrix is fine martensite (M), as well as the composite has the highest hardness and wear resistance. The lower or higher heating temperatures of quenching process all result in the decrease of hardness of the steel matrix, which leads to the wear resistance being lower than the as-cast composite.

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Rendez vous with Saturn's rings

International Astronomical Union Colloquium ◽

10.1017/s0252921100101885 ◽

1984 ◽

Vol 75 ◽

pp. 743-759 ◽

Cited By ~ 2

Author(s):

Kerry T. Nock

Keyword(s):

Solar Energy ◽

Electric Propulsion ◽

Power Source ◽

Propulsion System ◽

Low Thrust ◽

Ring Plane ◽

The Earth ◽

Total Impulse ◽

Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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