Dispersing nano-AIN particles cluster by designing Al-Si-AIN/Mg diffusion couples and the preparation of AIN/Mg-Al composite

摘要

In this paper, an Al-Si-AlN/Mg diffusion couple has been designed by inserting the master alloy rod into nearly solidified Mg melt, followed by re-heating procedure. It was found that the outward diffusion of Al and inward diffusion of Mg result in the generation of several typical areas among the couple. The formation of Mg17Al12 eutectic phase was detected and the size of nano-sized AlN particle clusters was obviously reduced. When the diffused couple was introduced into Mg melt to produce 0.8AlN/Mg-8Al-0.4Si composite, relatively uniform distribution of AlN particles has been achieved. The tensile strength of the as-cast composite was found to be 221 MPa tested at 25 degrees C and 148 MPa at 200 degrees C. This paper may provide suggestions for microstructural control of composite preparation by introducing the master alloys with one matrix into another melt.