Papers by Keyword: Thermal Desorption Spectrometry

Abstract: The hydrogen embrittlement of a low carbon HSLA steel has been investigated by means of slow strain rate test (SSRT) on circumferentially notched specimens. Hydrogen was introduced into specimens by electrochemical charging and the diffusible hydrogen content was measured by thermal desorption spectrometry (TDS) analysis. The activation energy of hydrogen desorption in the present steel was calculated to be 12.75 kJ/mol after TDS analysis. The peak stress and displacement during notch tensile tests had been found to decrease simultaneously with diffusible hydrogen content, which could be expressed by two power law relationships, respectively. Fracture surface was a cleavage type indicating that the steel had high susceptibility of hydrogen embrittlement.

Abstract: Hydrogen absorption of incoherent TiC particles that were once reported to be strong hydrogen traps in iron at room temperature was investigated by means of thermal desorption spectrometry (TDS). The results indicated that incoherent TiC particles in iron do not trap hydrogen at all at room temperature even they are cathodically charged for a long time. Only at high temperatures and in atmosphere containing hydrogen source, incoherent TiC particles can trap hydrogen. The origin of hydrogen trapped by incoherent TiC particles was justified to be water vapor in the atmosphere during heat treatment.

Abstract: A new method has been developed to determine the activation energy for hydrogen desorption from steels by means of thermal desorption spectrometry (TDS). This method directly fits the Kissinger’s reaction kinetic formula dX/dt=A(1-X)exp(-Ed/RT) to experimentally measured thermal desorption spectrum and best fit yields the activation energy (Ed) and the value of constant A. It has been proven that this new method is applicable to precise measurement of the activation energy for hydrogen desorption from incoherent TiC particle, coherent TiC precipitate, grain boundary and dislocation in 0.05C-0.20Ti-2.0Ni and 0.42C-0.30Ti steels.