Mechanical hardness estimation of heat-treated DIN50Cr3 spring steel utilizing laser-induced breakdown spectroscopy (LIBS) inverse calibration

Novel Surface Topography and Microhardness Characterization of Laser Clad Layer on TC4 Titanium Alloy Using Laser-Induced Breakdown Spectroscopy and Machine Learning

“…For example, the hardness of tungsten heavy alloy samples after plasma irradiation was investigated via the intensity ratio of ionic to atomic spectral lines of W. [40] Similarly, the ratio of ionic to atomic emission lines was utilized to measure the Vickers hardness of low-carbon spring steel. [41] In another study, [26] the authors reported that the plasma excitation temperature revealed a linear relation with the hardness values of bio-ceramic samples. The results indicated that the measured hardness based on these measurements poses better reproducibility than the Vickers hardness measurements.…”

Research on a LIBS-based detection method of medium-and-low alloy steel hardness

“…The key parameter indexes of LS-SVM are input vectors, kernel function types, and corresponding parameters. The objective optimization function of the LS-SVM algorithm is shown in formula (6), and the function constraints are shown in formula (7).…”

“…The results showed that the magnesium line intensity ratio of the two materials had a linear relationship with the hardness of the sample. Mohamed M. EIFaham et al 6 constructed calibration curves based on the ratio of ion-atomic line intensity to Vickers mechanical hardness from LIBS spectra of three spring steel samples DIN50Cr3, which underwent different heat treatments. The curves were analyzed in terms of their microstructures, and results showed that the hardness was correlated with the microstructure experiencing different heat treatments.…”

Using laser-induced breakdown spectroscopy to characterize the surface mechanical properties of soft materials

“…Recently, its application as an innovative method for in situ characterizing materials’ surface mechanical properties has been validated frequently. 11–36 All papers found regarding this topic used materials with strengths much larger than dozens of MPa (hereinafter defined as solid materials) such as concretes, 11 mineralized biological materials, 12–15 bulk metals, 16–28 ceramics, 29,30 stones, 31–35 and pharmaceutical tablets. 36 In almost all of these papers, the method was developed in light of the role of the shock wave in the expansion of a laser-induced plasma from a solid material after the end of a laser pulse.…”