Annealing-Induced Enhancement in Mechanical Strength and Corrosion Resistance of Spark-Plasma-Sintered Fe-Based Bulk Metallic Glasses

Abstract:

FeCrMoBC bulk metallic glasses (BMGs) were synthesized via spark plasma sintering (SPS) technique, and subsequent heat treatment was applied to optimize their properties. The effects of annealing on the microstructure, mechanical behavior, and corrosion resistance of the Fe-based BMGs were investigated. Results show that under optimized SPS parameters (sintering temperature of 560 °C, consolidation pressure of 550 MPa, and holding time of 1 min), the as-sintered sample achieves a relative density of 94.40% and a compressive strength of 678 MPa. After heat treatment at 550 °C for 20 min, an amorphous matrix with enhanced mechanical properties can be obtained: the compressive strength increases to 884 MPa, accompanied by superior corrosion resistance, which is characterized by corrosion potential (E_corr) of -0.318 V, corrosion current density (I_corr) of 2.098×10^-7 A/cm², and polarization resistance (R₂) of 59 379 Ω·cm². Notably, annealing at 650 °C for 20 min results in a maximum relative density of 97.23% and a peak microhardness of 758.86 HV, which is attributed to the crystalline phase precipitation and grain refinement. These results demonstrate that controlled heat treatment can effectively improve the densification and comprehensive properties of SPS-processed Fe-based BMGs by regulating the microstructure evolution.