| Abstract Scope |
We studied the phase transition during GTAW butt-welding of martensitic Low Temperature Transformation (LTT) steel in Neutron-Bragg-Edge Imaging (NBEI) experiments [1]. The austenitization in the heat affected zone (HAZ) could be clearly visualized at λ = 0.39 nm, a wavelength smaller than the Bragg edge wavelengths of both austenite and martensite. Further, the re-transformation upon cooling from austenite into martensitic phase was detected. However, we observed an unexpected additional change in transmission at λ = 0.44 nm, a wavelength larger than the wavelengths of the Bragg edges of both the martensitic and austenitic phases. We attribute this change to the Debye-Waller-Factor that describes the temperature dependence of coherent scattering at a crystal lattice [2].
[1] A, Griesche et al., Appl. Sci, 2021, 11, 10866.
[2] R, Jamro; T, Mente; N, Kardjilov; H, Markötter; AM, Al-Falahat; R, Woracek; I, Manke; A, Griesche J. of Phys.: Conf. Series 2023, 2605(1): 012026. |