Effect of W on the thermal stability, mechanical properties and corrosion resistance of Fe-based bulk metallic glass

In this work, the effect of refractory metal W on the thermal stability, mechanical properties and corrosion resistance of Fe36Cr23Mo18-XWXC15B6Y2 (X = 0, 3, 5, 8, 10, 12, 15, 18) bulk metallic glasses (BMGs) were systematically investigated. The results showed that a wide composition range could be quenched to form BMG when the considerable refractory metal was introduced, although the higher mixing enthalpy of W than Mo between other elements (such as Fe, Cr, C) incited the deterioration of glass forming ability (GFA). The introduction of W significantly improved the thermal stability of the alloy system with glass transition temperature Tg and onset crystallization temperature Tx of Fe36Cr23Mo8W10C15B6Y2 BMG reached 923 K and 972 K, respectively. The W-bearing Fe-based BMGs also exhibited a very high hardness of 1400 HV and Young's modulus of 271 GPa, respectively. The extremely high thermal stability and elastic modulus were mainly derived from the strong chemical bonding between atoms. In addition, the large addition of W reduced the corrosion current density of the original alloy by an order of magnitude, which was mainly due to the formation of WO3 and the increase of MoO2 in the passivation film which inhibit the pit initiation and pit growth.