Consolidation of commercial pure aluminum particles by hot ECAP

Al-Ti-C master alloys have been widely investigated by various researchers. However, their refining effectiveness is still severely compromised by the preparation process. In this work, the aluminum melt in-situ reaction was carried out to synthesize the Al-5Ti-0.62C, and its refining performance was estimated. The thermodynamics calculation and differential scanning calorimeter experiment were used to investigate the synthesis mechanism of TiC. Quenching experiment was conducted to explore phase and microstructure transformation of the Al-5Ti-0.62C system. The results show that the main phases of Al-5Ti-0.62C master alloys are α-Al, Al3Ti, and TiC and it has a positive effect on commercial pure aluminum refining. Commercial pure aluminum is completely refined into the fine equiaxed structure by adding 0.3% Al-5Ti-0.62C master alloy. TiC particles mainly distribute in the grain interior and grain boundaries. The excess Ti came from the dissolution of Al3Ti spreading around TiC and finally forming the Ti-rich zone to promote the nucleation of α-Al. The experiments certified that TiC was formed by the reaction between solid C and excess Ti atoms. The main reactions in the Al-5Ti-0.62C system were that solid Al is transferred into liquid Al, and then liquid Al reacted with solid Ti to form the Al3Ti. At last, the release of a lot of heat promotes the formation of TiC which formed by the Ti atoms and solid C.

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INVESTIGATION OF THE SEMISOLID MECHANICAL STIRRING METHOD TO DEPOSIT AN ALUMINUM PARTICLE COATING ON THE SURFACE OF SiC SHORT FIBERS

Surface Review and Letters ◽

10.1142/s0218625x04005986 ◽

2004 ◽

Vol 11 (02) ◽

pp. 205-210 ◽

Cited By ~ 1

Author(s):

XIAOHUA QIN ◽

DONGLIANG JIANG ◽

SHAOMING DONG

Keyword(s):

Aluminum Particle ◽

Pure Aluminum ◽

Single Layer ◽

Optical Microscope ◽

Composite Fiber ◽

Short Fibers ◽

Aluminum Particles ◽

Element Analysis ◽

Axial Section ◽

Mechanical Stirring

SiC short fibers, with an average diameter of 13 μm and length of 300–500 μm and chopped from SiC continuous fibers, were surface-modified by the semisolid mechanical stirring method to produce a discrete coating of aluminum particles. The SiC short fibers were introduced into semisolid state aluminum to prepare a slurry by the mechanical stirring method. As all of the short fibers were uniformly dispersed in the slurry, the temperature of the slurry was decreased as quickly as possible, but the slurry continued to be stirred until all of it was converted quickly into a powder-like composite. The surface morphology and axial section of the composite fiber and aluminum particles were examined using a scanning electron microscope (SEM) and an optical microscope; the element analysis of particles on the surface of short fibers in nanometer and submicron sizes was performed by Auger electron spectroscopy (AES). The results indicated that the powder-like composite was a mixture of pure aluminum powder and SiC short composite fiber, the surface of the composite fiber was coated by a discrete single layer of aluminum particles with nanometer, submicron and micron sizes, and the surface coverage of the aluminum particles on the surface of the short fibers ranged from 20 to 30%.

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