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Effect of Ultrasonic Vibration on Direct Reaction Between Solid Ti Powders and Liquid Al
Z.W. LIU, X.M. WANG, Q.Y. HAN, and J.G. LI
In-situ blocky Al3Ti particles can be synthesized by direct reaction between solid Ti powders and liquid Al in terms of reaction-peeling model. In this research, the eect of high-intensity ultrasonic vibration on the reaction was investigated by means of immersing the ultrasonic radiator in the Al melt at 1003 K (730 C)
during the fabricating process. The results show that the thickness of Al3Ti reaction layers can be decreased to range from 2 to 3 lm, and the sizes of most of Al3Ti
particles can be reduced in the ultrasonic elds as well, with the average size ranging from 2 to 3 lm. The two changes are both attributed to the eects of external forces produced in the ultrasonic elds. Thereby, small blocky Al3Ti particles can be peeled o from the reaction layer more quickly, making reaction layers to become thinner and the particles smaller.
DOI: 10.1007/s11661-013-2145-5 The Minerals, Metals & Materials Society and ASM
International 2013
In our previous research,[1] we discussed the formation mechanism of small blocky in-situ Al3Ti particles via direct reaction between solid Ti powders and liquid
Al. A related reaction-peeling model was applied to illustrate the reaction process of solid Ti in the liquid Al, which involved in the following process: the nucleation of Al3Ti, the growth of Al3Ti, and the rupture of Al3Ti.
As a result, a simple method for fabricating in situ Al3Ti/Al composites was proposed. How to decrease the size of in situ-formed Al3Ti particles further has become a new interesting research topic for us.
Ultrasonic vibration has been extensively used in the purifying, degassing, and the renement of metallic melt,[2,3] as well as the fabrication of in situ particulate-reinforced metal matrix composites,[4,5] as the injection of ultrasonic elds in a liquid can give rise to nonlinear eects, such as cavitation, acoustic streaming, and high local pressure.[6]
Some related study has demonstrated that high-intensity ultrasonic vibration can break up the clusters of reinforced particles in the matrix. Specially, long rod-like Al3Ti particles can be broken into small blocky ones in the ultrasonic elds.[79] However, very little research has been reported on the eect...