An approach of stand-off measuring hardness of tungsten heavy alloys using LIBS

Investigation of compositional analysis and physical properties for Ni-Cr-Nb alloys using laser-induced breakdown spectroscopy

“…Essentially, this formula can be applied for Ni-Cr-Nb alloys evaluated at the same experimental conditions. The same trend has been previously reported by COWPE et al [35] for bioceramics and by SATTAR et al [16] for tungsten heavy alloys. They revealed that the plasma shockwave velocity also influenced the value of plasma electron temperature.…”

“…10. As the electron density directly depends on the rate of ablated mass of material, and the latter is inversely related to hardness, we can conclude that N e decreases if the materials become harder [16].…”

“…12 shows the variation of electron temperature with increasing thermal conductivity K. There is a linear decrease in T e of alloys and it could be represented by a semi-empirical formula as K = 163 -135T e . The reason of T e variation is attributed to a reduction of ablation efficiency (low ablation rates) with an increase in thermal conductivity [16]. In fact, the laser energy that reaches the bulk material generates heat, which will reside longer into the materials with a lower thermal conductivity, leading to remarkable mass removal enhancement.…”

“…It was experimentally confirmed that the repulsion of the shock wave on the hard materials is much strong to produce a high-speed shock wave. Consequently, enough temperature is generated just behind the shock wave to ionize the atoms leading to an increase in ionic emission intensity in comparison with the intensity of neutral emission [16]. Moreover, studies revealed that the hardness of various materials can be evaluated by monitoring the plasma parameters, i.e.…”

Estimation of Grain Size in Randomly Packed Granular Material Using Laser-Induced Breakdown Spectroscopy

“…The first paper regarding this topic was published in 2006, in which authors found a monotonic response of the emission intensity ratio of calcium lines with the surface strength of the concrete samples [12]. Since then, LIBS has been widely deemed as a promising hardness testing tool for various materials, such as tissues [13,14], steels and alloys [15][16][17][18][19][20], ceramics [21], and stones [22], via monitoring the variations of the parameters obtainable from plasma emission measurements, including spectral line intensity, excitation temperature, and electron density in plasma. Despite these excellent attempts to expand the scope of LIBS application, to the best of our knowledge, no experiments have been conducted aiming to investigate a possible approach for estimating grain size in RPG materials using LIBS.…”