Microstructural evolution of laser-processed CuZrTi alloy during liquid metal dealloying

The possibility of topology modification at the design stage makes metal additive manufacturing (AM) a promising approach for coupling with liquid metal dealloying (LMD) to synthesize novel hierarchical materials. However, elemental microsegregation in the precursor fabricated by AM leads to compositional and phase heterogeneity, which inevitably affects the dealloying process. In this work, the AM–LMD process chain is pioneered to explore the microstructural evolution of a laser-processed CuZrTi precursor, synthesized via powder bed fusion, on the dealloying kinetics and the formation of ligament microstructure. The results demonstrate that the dealloying of laser-processed materials is strongly affected by compositional heterogeneity. According to a systematic analysis, the size of the ligament varies up to ∼ 2.6 μm in the region corresponding to the 2nd stage of dealloying and correlates with the observed heterogeneity inside the laser-processed precursor. A heterogeneous stepwise (two-stage) dealloying reaction is observed. The formation of the 2nd dealloying stage is attributed to the saturation of the Mg channels by Cu during the 1st stage, which is unique for each dealloying condition. For the same immersion time, the average atomic fraction of Cu dissolved in Mg during the 1st stage of dealloying increases with temperature. This study provides insight into the effects of compositional heterogeneity in laser-processed materials during LMD, highlighting new challenges in achieving compositional homogeneity and phase stability.