Quantification of vanadium precipitates in HSLA steel by synchrotron X-ray absorption spectroscopy (XAS)

Abstract

This study demonstrates how the synchrotron X-ray absorption spectroscopy can be applied for the quantification of precipitation in high strength low alloyed steel. The fraction of vanadium in different forms of compounds, as well as in the solid solution, was measured using a linear combination fit of the spectral weights. The technique confirms substantial enhancement of precipitation by lowering the cooling rate. A significant fraction of vanadium atoms of over 0.6 remained in the solid solution when the cooling rate was as high as 60 K × s−1. In contrast, the precipitation of vanadium was almost completed by decreasing the cooling rate to 0.1 K × s−1. The results corresponded to the proof by scanning transmission electron microscopy.

A Control‐Cooled Hot‐Forged Medium Carbon V‐Microalloyed Steel: Strengthening Breakdown in Conjunction with the Synchrotron X‐Ray Absorption Spectroscopy

“…The V K ‐edge XAS measurement was carried out at Synchrotron Light Research Institute (SLRI), Thailand, at Beamline 8, in a similar way as a former work. [ 18 ] The V(C,N), VC, and VN high purity powders, the same as used in the former work, [ 18 ] were measured for the standard spectra in transmission mode employing a 40 mm‐long ionization chamber containing argon and helium gas mixture. The complete dissolution of vanadium after solution annealing in the as‐received bars was proven by scanning transmission electron microscopy on a carbon replica sample.…”

“…Alternative method using synchrotron X-ray absorption spectroscopy (XAS) in identifying and quantifying the vanadium precipitates has proven its potential in V-added high strength low alloyed steels as established in several works. [18][19][20] The current article, will, therefore, represent this analytical method together with the assessment of strengthening mechanisms, which reflects the effectiveness of vanadium consumption for precipitation hardening. Such findings cannot be quantified by any other characterization method.…”

The Synchrotron Radiation for Steel Research

“…XAS technique has been applied for different steels at beamline BL8 of the Siam Photon Laboratory (SPL) at Synchrotron Light Research Institute (SLRI), Nakhon Rachasima, Thailand. The first investigation, as published elsewhere [7], reveals the type and amount of Vanadium precipitates as a result of the cooling rate after simulated hot rolling process in HSLA steel. The size of Vanadium precipitates varies from several nanometers to 70 nm by Scanning Transmission Electron Microscopy (STEM).…”

Precipitation Simulation and X-Ray Absorption Spectroscopy for Hot Rolled v-Hsla Steel

“…60, 5 and 0.1 C/s, were selected to measure vanadium K-edge absorption spectra in a fluorescent mode. A beam with a cross section of 1  16 mm penetrating down to 100 m results in an illuminated volume of 1.6 mm 3 [15] Standard powdered compounds of VC, VN and V(C,N) were prepared in a thin layer film and then measured in transmission mode as the standard spectra for the Linear Combination Fit (LCF). The solution-annealed sample can be used for the standard spectrum of vanadium in solid solution as proven earlier in [32].…”