2007 Volume 48 Issue 7 Pages 1797-1801
Amorphous Mg65Cu20Y10Ag5/nano ZrO2 composite alloys are fabricated through mechanical alloying (MA) in the planetary mill, using amorphous matrix alloy prepared by melt spun and 3 vol% spherical nano-sized ZrO2 particles. The specimens were hot pressed in Ar atmosphere under the pressure of 700 MPa at the temperature of soft point which is determined by TMA (Thermo mechanical Analysis). The hot-pressed composite alloy can reach to a 96% density, the hardness of 315±10 in Hv scale, and the compressive strength of 690 MPa. In addition, the result of mechanical test revealed that the nano-sized ZrO2 dispersion can obviously increase hardness as well as toughness of the Mg based amorphous alloy. Moreover, after compression test at 426 K (sample has been deformed 60 vol%), the hardness of hot-pressed composite alloy dramatically increases to Hv 400±25. An image of shear band being stopped in front of the ZrO2 particle was found by the TEM observation. Base on these two evidences, suggests that the strength of amorphous Mg65Y10Cu20Ag5 with 3 vol% ZrO2 composite alloy could be potentially improved by healing its residue porosity with hot deformation method within the supercooled liquid temperature region.