Effects of rare‐earth elements on the glass‐forming ability and mechanical properties of Cu ₄₆ Zr _{47− <i>x</i>} Al ₇ M _<i>x</i> (M = Ce, Pr, Tb, and Gd) bulk metallic glasses

Abstract

Abstract Cu 46 Zr 47− x Al 7 M 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 46 Zr 47− x Al 7 M x were investigated. The GFA of Cu 46 Zr 47− x Al 7 M x (M = Ce, Pr) alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu 46 Zr 47− x Al 7 Tb x ( x = 2, 4, and 5) amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu 46 Zr 47− x Al 7 Gd x ( x = 2, 4, and 5) increases with increasing Gd. T x and T p of all decrease. T g is dependent on the rare‐earth element and its content. Δ T x for most of these alloys decreases except the Cu 46 Zr 42 Al 7 Gd 5 alloy. The activation energies Δ E g , Δ E x , and Δ E p for the Cu 46 Zr 42 Al 7 Gd 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 46 Zr 45 Al 7 Tb 2 alloy presents the highest microhardness, Hv 590, while the Cu 46 Zr 43 Al 7 Pr 4 alloy presents the least, Hv 479. The compressive strength ( σ c.f. ) of the Cu 46 Zr 43 Al 7 Gd 4 BMG alloy is higher than that of the Cu 46 Zr 43 Al 7 Tb 4 BMG alloy.