Effects of rare-earth elements on the glass-forming ability and mechanical properties of Cu^sub 46^Zr^sub 47-x^Al^sub 7^M^sub x^ (M = Ce, Pr, Tb, and Gd) bulk metallic glasses

Cu^sub 46^Zr^sub 47-x^Al^sub 7^M^sub x^ (M = Ce, Pr, Tb, and Gd) bulk metallic glassy (BMG) alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability (GFA), thermal stability, and mechanical properties of Cu^sub 46^Zr^sub 47-x^Al^sub 7^M^sub x^ were investigated. The GFA of Cu^sub 46^Zr^sub 47-x^Al^sub 7^M^sub x^ (M = Ce, Pr) alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu^sub 46^Zr^sub 47-x^Al^sub 7^Tb^sub x^ (x = 2, 4, and 5) amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu^sub 46^Zr^sub 47-x^Al^sub 7^Gd^sub x^ (x = 2, 4, and 5) increases with increasing Gd. T ^sub x^ and T ^sub p^ of all decrease. T ^sub g^ is dependent on the rare-earth element and its content. ΔT ^sub x^ for most of these alloys decreases except the Cu^sub 46^Zr^sub 42^Al^sub 7^Gd^sub 5^ alloy. The activation energies ΔE ^sub g^, ΔE ^sub x^, and ΔE ^sub p^ for the Cu^sub 46^Zr^sub 42^Al^sub 7^Gd^sub 5^ BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respectively. The Cu^sub 46^Zr^sub 45^Al^sub 7^Tb^sub 2^ alloy presents the highest microhardness, Hv 590, while the Cu^sub 46^Zr^sub 43^Al^sub 7^Pr^sub 4^ alloy presents the least, Hv 479. The compressive strength (σ ^sub c.f.^) of the Cu^sub 46^Zr^sub 43^Al^sub 7^Gd^sub 4^ BMG alloy is higher than that of the Cu^sub 46^Zr^sub 43^Al^sub 7^Tb^sub 4^ BMG alloy.[PUBLICATION ABSTRACT]