Heterogeneous material 3D printing: from multi-material integration to spatiotemporal functionality programming

Heterogeneous material 3D printing (HM3DP) represents a transformative approach in additive manufacturing, enabling precise spatial control over material composition, microstructure, and functionality. This technology transcends the limitations of homogeneous fabrication by integrating multi-material systems, dynamic process programming, and external field modulation, offering innovative solutions for biomimetic structures, flexible electronics, and smart devices. This review systematically examines the chemical foundations, process innovations, and applications of HM3DP and proposes a three-tier classification system—composition, structure, and functional-temporal heterogeneity—to standardize evaluation metrics. Key challenges, including dynamic interface compatibility, cross-scale heterogeneous mechanical integrity and fracture control, and functional-temporal synergy, are critically analyzed. Future directions emphasize multi-physics collaboration and intelligent optimization to achieve adaptive, high-performance heterogeneous systems. HM3DP is poised to bridge the gap between static manufacturing and dynamic, intelligent design, unlocking new frontiers in materials science and engineering.