Tm对锆基块体非晶合金力学性能和腐蚀性能的影响

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

摘要:

采用铜模负压吸铸工艺制备了(Zr_0.6336Cu_0.1452Ni_0.1012Al_0.12)_100-xTm_x（x=0~5，原子分数）块体金属玻璃（BMG）合金，研究了Tm对合金力学性能和抗腐蚀性能的影响。结果表明，当Tm含量增加到3%时，其玻璃形成能力（GFA）和压缩塑性显著提高，但过量Tm会降低GFA。x=3时合金的最大过冷液相区宽度为100 K，抗压强度为1669 MPa，塑性应变为21.01%，远高于Zr_0.6336Cu_0.1452Ni_0.1012Al_0.12 BMG的各项性能（67 K、1439 MPa和5.90%）。然而，电化学测试结果表明，x=3时的合金在3.5%（质量分数）NaCl溶液中的耐腐蚀性不佳，且其耐腐蚀性和力学性能随Tm含量的变化趋势与预期不同。可能是由于过量添加稀土元素Tm，容易形成更多的氧化物，导致点蚀加剧。进一步添加Tm可以提高Zr基BMG钝化膜的完整性和耐点蚀性能，但力学性能不理想。

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.