Synchronously improving glass forming ability and mechanical properties by Pd alloying Zr-Al-Cu bulk metallic glass

In this work, the influences of Pd addition on the glass-forming ability (GFA), thermal behaviors, mechanical properties and microstructure of the Zr₆₀Al₁₀Cu₃₀ bulk metallic glasses (BMGs) were systematically investigated. Our study shows that proper addition of Pd can simultaneously improve the GFA, strength and plasticity of BMGs. The BMGs with Pd contents of 2.5 at.% and 5 at.% exhibit high GFA of 10 mm and 12 mm, high strength of 1852 MPa and 1858 MPa, and good plasticity of 4.3 % and 5.9 %, respectively, all of them are much higher than those of Zr₆₀Al₁₀Cu₃₀ BMGs. It is revealed that alloying BMGs with proper Pd promotes the formation of a higher degree of icosahedral clusters, which is responsible for improved GFA and strength, and simultaneously encourages a decrease in the volume of shear transition zone (STZ) and the amount of imperfect ordered packing (IOP) clusters, which are responsible for the enhanced plasticity. Our findings indicate that the synergistic effect of short-range ordered structures induced by alloying amorphous alloys plays an important role in simultaneously improving the GFA and mechanical properties, providing valuable insights for BMG design.