Mechanical Properties of the Hot-Pressed Amorphous Mg₆₅Cu₂₀Y₁₀Ag₅/NanoZrO₂ Composite Alloy

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 700MPa 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.