Effects of pre-compression on the microstructure, mechanical properties and corrosion resistance of Cu47.5Zr47.5Al5 bulk metallic glasses

The effects of pre-compression treatment at room temperature on the microstructures, mechanical properties, and corrosion resistance in the seawater solution of Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) have been investigated. The amount and size of B2-CuZr nanocrystallites precipitated from the glass matrix increase with enhancing the pre-compression stress, which suggests that the appropriate pre-compression treatment promotes the formation of metallic glass matrix composites (MGMCs). The 850 MPa pre-compressed MGMC possesses the highest compressive fracture strength (1814 MPa) and a certain degree of plasticity, as well as the larger hardness of 700 HV. The 1415 MPa pre-compressed MGMC with more B2-CuZr nanocrystallites demonstrates advantages in thermal stability and corrosion resistance in the seawater solution. It shows the higher corrosion resistance with the most positive corrosion potential and the lower corrosion current density than the other tested samples. These can be attributed to the structural homogeneity after appropriate precipitation of nanocrystallites.