Optimization of submicron TiB2 particle distribution in aluminum matrix composites by ultrasonic vibration and its effect on mechanical properties
The 9 mass%TiB2 particles in-situ reinforced Al-4.5Cu aluminum matrix composites were successfully prepared using the molten salt-metal reaction method.The improvement effect of ultrasonic vibration(UV)treatment on the distribution of agglomerated submicron TiB2 particles was studied.The results show that the cavitation effect and acoustic streaming effect generated by ultrasonic vibration effectively eliminate the phenomenon of particle aggregation in the melt.After 4 min of ultrasonic treatment,TiB2 particles are uniformly dispersed throughout the entire melt,and small agglomerations formed by TiB2 particles smaller than 100 nm are also dispersed.After solidification of the composites,some TiB2 particles smaller than 400 nm are dispersed in the matrix near the grain boundary.After 4 min of ultrasonic vibration treatment,the yield strength of the composites increases by 119%and 64.3%compared to the matrix alloy and the composites without ultrasonic vibration treatment,respectively.This is mainly due to the fine and dispersed distribution of TiB2 particles in the matrix of the composites caused by ultrasonic vibration treatment,which enhances the Orowan strengthening and thermal expansion mismatch strengthening effects,thereby increasing its strength.
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