- By:
- Kannan, Rangasayee ; Rodriguez Parra, Mario A; Hoffmann Rodriguez, Miguel A; Wang, Yiyu ; Marquez Rossy, Andres E; Nandwana, Peeyush ; Lee, Yousub
- Journal Name:
- Materials and Design
- Page Number:
- 115749
- Volume:
- 264
- Publication Date:
- March 11, 2026
- View DOI Listing:
- https://doi.org/10.1016/j.matdes.2026.115749
Abstract
In this study, we demonstrate that spatially resolved cooling curves derived from real-time infrared (IR) thermography during additive manufacturing (AM) can capture spatial variations in phase transformation temperatures through cooling curve analysis (CCA). Using this approach, we show that during laser hot-wire deposition of 410 stainless steel (410SS), the martensite start temperature (Ms) evolves dynamically throughout the build. The Ms temperature is spatially nonuniform, ranging from 185 °C to 348 °C, with the lowest values toward the build center and higher values toward the upper region of the deposit. In the lower portion of the build, no Ms inflection is detected via CCA, consistent with transformation occurring earlier during thermal cycling followed by tempering during subsequent thermal cycles. These trends in Ms are corroborated by characterizing the microstructure by electron backscatter diffraction (EBSD). Traditionally, Ms is assumed to be constant, and a single interpass temperature is applied during both deposition and residual stress modeling. Our results demonstrate that IR-derived cooling curves provide a route to spatially and temporally resolved transformation temperature tracking for dynamic interpass control and improved residual-stress modeling.
