Crack Mitigation in Fe-Cu Hybrid Materials for Additive Manufacturing: A Study of Build-Plate Preheating in DED-LB/M

Abstract This study investigates the effect of preheating the build-plate on in situ mixed Fe-Cu compositions - specifically 50% 316L SS - 50% CuCr1Zr and 25% 316L SS - 75% CuCr1Zr blends - to mitigate cracking issues typically observed in functionally graded Fe-Cu materials (FGM). The primary challenge in laser deposition of F is the development of internal stresses. These stresses result from the significant differences in the physical properties of copper/bronze and steel, their limited miscibility, and the formation of brittle interfacial phases, along with complex variations in the mechanical and physical properties of the resulting alloy. Collectively, these factors can lead to various types of cracking in the final components. Preheating the build-plate to elevated temperatures is evaluated as a strategy to alleviate these detrimental effects and enhance the overall performance and reliability of the multi-material components. The thin-walled Fe-Cu compositions were manufactured according to two preheating conditions: room temperature and 600 °C preheating for two Fe-Cu compositions. The influence of preheating on defect formation and material integrity under different conditions is analyzed through microstructural examinations using optical and scanning electron microscopy (SEM). The analysis includes the quantification of crack width and length. The findings demonstrated a notable decrease in cracking at a moderate preheating temperature of 600 °C and suggest that it provided a good condition for thermal stresses mitigation and strengthening of the bonding between Fe and Cu. These findings highlight the importance of effective thermal management in directed energy deposition laser-based (DED-LB) processes for achieving robust Fe–Cu FGMs. Leveraging the demonstrated benefits of thermal management in this study, future research can extend similar strategies to other additively manufactured multi-materials, enabling tailored material properties and high-performance applications.