Effect of Tm on Mechanical and Corrosion Properties of Zr-Based Bulk Metallic Glasses

Abstract:

A series of (Zr_0.6336Cu_0.1452Ni_0.1012Al_0.12)_100-xTm_x (x=0~5, at%) bulk metallic glass (BMG) alloys were fabricated by copper mold suction casting, and the effect of Tm on the mechanical and corrosion properties were investigated. The results show that when Tm content increases to 3at%, the glass forming ability (GFA) and compressive plasticity are significantly improved, whereas GFA is decreased by adding excessive Tm. The maximum supercooled liquid region width (ΔT_x) of the alloy with x=3 is 100 K, the compressive fracture strength is 1669 MPa, and the plastic strain is 21.01%, which are much higher than those of the Zr_0.6336Cu_0.1452Ni_0.1012Al_0.12 BMG (67 K, 1439 MPa, and 5.90%). However, the electrochemical test results show that the alloy with x=3 does not have excellent corrosion resistance in 3.5wt% NaCl solution, and the change trend of corrosion resistance and mechanical properties with Tm content is different from the expectation. The possible reason is that the excessive addition of rare-earth element Tm easily causes more oxides, which leads to the severe pitting corrosion. Further addition of Tm can improve the integrity and pitting corrosion resistance of Zr-based BMG passivation film, but the mechanical properties are not ideal.