Microstructure and Properties of Fe₃Al/TiB₂ Composites Formed by Selective Electron Beam Melting with Different Powder Processes

This study compares Fe–28Al–5Ti–1.3B composites fabricated via selective electron beam melting (SEBM) using ball-milling and gas atomization powders. Ball-milling powders achieve partial alloying; higher SEBM energy density (24 vs 15 J mm⁻³) is required to promote uniform recrystallization (97.3% recrystallized grains), stabilize grain boundaries, and enhance stress homogeneity. Gas atomization powders, though fully alloyed, exhibit uneven temperature gradients due to larger particles and lower energy input, resulting in deformation zones (14.4% deformed grains) and poor intragranular stress states. Mechanically, composites prepared by ball milling show superior hardness (520.3 HV) and compressive strength (476.8 MPa) but brittle fracture (0.35% strain), while composites prepared by gas atomization display lower compressive strength (218 MPa) and higher plasticity (10% strain). This study reveals for the first time that the ball-milling process can induce uniform recrystallization in SEBM although partial alloying and high energy input. This provides a new idea for the design of high-strength Fe–Al materials besides traditional gas atomization method.