Microstructure and mechanical properties of additively manufactured Invar alloys: A critical review

Invar alloy, as a typical low-expansion alloy material, has broad application prospects in aerospace and precision instrumentation fields. However, with the increasing demands for the comprehensive performance and structural precision of Invar alloy components in advanced equipment supports, the limitations of traditional manufacturing methods for Invar alloys have become increasingly obvious. Additive manufacturing technology demonstrates significant advantages in the near-net shaping of complex components and the optimization of alloy properties, offering potential solutions to the difficulties of low strength, poor machinability, and changeable temperature range associated with Invar alloys. This review focuses on analyzing and summarizing relevant research findings regarding the optimization of microstructure, performance, and applications of Invar alloys through additive manufacturing technology. Additionally, it consolidates recent exploratory studies on the engineering applications of additively manufactured Invar alloys. Finally, this paper anticipates key challenges that need to be addressed in future research on the additive manufacturing of Invar alloys.