Effects of recycled powder on the microstructure and mechanical properties of TC4 alloy by selective laser melting

Selective laser melting technology has demonstrated significant advantages in the processing of TC4 titanium alloy. While TC4 alloy exhibits outstanding properties, the economic viability of recycling its high‐cost powder has become a focal point of interest. Experimental results indicate that as the number of powder recycling cycles increases, the microstructure of the TC4 components tends to degrade gradually. After multiple recycling cycles, the intensity of the crystal diffraction peaks diminishes, and the crystal structure undergoes changes due to oxidation, stress accumulation, and microstructural damage. The hardness of the components fluctuates with the increasing number of recycling cycles. Components made from non‐recycled powder exhibit high tensile strength, but this strength gradually declines with additional recycling cycles, showing a brief recovery after 20 cycles. The impact toughness slightly improves after five recycling cycles, but it then continues to decrease, stabilizing after 30 cycles of recycling.