Influence of Heat Treatment Temperature on the Structure and Mechanical Properties of Modified MA6000 Alloy Fabricated by Spark Plasma Sintering

This study investigated the effect of heat treatment temperatures on the microstructure and mechanical properties of MA6000 alloy, produced via spark plasma sintering. The MA6000 alloy, enhanced with Fe, Mn, Zr, and Y2O3 additions for improved heat resistance, underwent heat treatments at 1000°C, 1100°C, and 1200°C. Results show that at 1000°C, the original microstructure was maintained with minimal grain growth, while at 1200°C, significant recrystallization occurs, leading to new grain formation and distinct grain boundaries. Relative density and porosity remained stable at approximately 98% and 0.5-0.9% respectively up to 1100°C. However, at 1200°C, relative density increased to 99.2% and porosity decreased to 0.1%, indicating a highly densified structure. Hardness decreased significantly from 582 HV to 410 HV with increasing annealing temperature, suggesting the need for balanced heat treatment conditions to optimize material properties. XRD analysis revealed the formation of protective Cr2O3 layers at 1000°C and 1100°C, while at 1200°C, the presence of Fe3O4 indicated higher oxidation levels, although the primary Ni phase remained unoxidized. These findings highlight the importance of heat treatment in adjusting the microstructural and mechanical properties of MA6000 alloy, providing valuable insights for optimizing its performance in high-temperature applications.