In this work, nanocrystalline AZ31 magnesium alloy powders, reinforced by submicron TiB
2 particles, were prepared via mechanical milling. It was found that TiB
2 particles stimulated the fracture and welding of AZ31/TiB
2 powders, leading to the acceleration of the milling process.
[...] Read more.
In this work, nanocrystalline AZ31 magnesium alloy powders, reinforced by submicron TiB
2 particles, were prepared via mechanical milling. It was found that TiB
2 particles stimulated the fracture and welding of AZ31/TiB
2 powders, leading to the acceleration of the milling process. Meanwhile, the TiB
2 particles were refined to submicron-scale size during the milling process, and their distribution was uniform in the Mg matrix. In addition, the matrix was significantly refined during the milling process, which was also accelerated by the TiB
2 particles. The formation of grain boundary segregation layers also led to the weakened TiB
2 peaks in the XRD patterns during the mechanical milling. The grain sizes of AZ31–2.5 wt % TiB
2, AZ31–5 wt % TiB
2 and AZ31–10 wt % TiB
2 powders were refined to 53 nm, 37 nm and 23 nm, respectively, after milling for 110 h. Under the combined effect of the nanocrystalline matrix and the well-dispersed submicron TiB
2 particles, the AZ31/TiB
2 composites exhibited excellent micro-hardness. For the AZ31–10 wt % TiB
2 composite, the micro-hardness was enhanced to 153 HV0.5.
Full article