The present work is motivated by the numerous applications of short lasers–ceramics interaction. It aims at applying a newly developed model to investigate the dynamic of laser-induced plasmas from a ceramic material into a helium gas under atmospheric pressure. To have a better understanding of the link between the material properties, the plume characteristics and its interaction with the laser beam, a thorough examination of the entire ablation processes is conducted. Comparison with the behavior of laser-induced plumes under the same conditions from a pure material is shown to have a key role in shedding the light on what monitors the plume expansion in the background environment. Plume temperatures, velocities, ionization rates as well as elemental composition have been presented and compared under carefully chosen relevant conditions. This study is of interest for laser matter applications depending on the induced plasmas dynamics and composition.

In this study, the effect of titanium addition on the microstructure and wear behavior ofHadfield steel was investigated. To do so, four groups of samples with different titaniumcontents of 0, 0.2, 0.4 and 0.6 wt% were prepared. After casting, the samples wereaustenitized at 1100 °C for 3h and quenched in water subsequently for solution treatment. Themicrostructure of the samples was investigated using an optical microscope (OM) andscanning electron microscope (SEM). For more studies the carbide composition was analyzedvia energy-dispersive spectroscopy (EDX). A wear test was performed via a pin-on-disk weartesting machine. The results show that after heat treatment the microstructure of thetitanium-free sample is fully austenitic, while the other samples show an austeniticstructure with non-continuous carbide precipitates. It was also revealed that titaniumaddition improves the hardness and wear resistance of the samples. The highest wearresistance was observed in the sample with 0.6 wt% titanium content. It was also shownthat the predominant wear mechanisms are adhesive and tribo-chemical. Beyond this, theeffect of cold working via a hammering treatment was studied on the samples and revealedthat austenite-to-martensite transformation improves the hardness and wear resistancesignificantly.

In this work, the high-temperature behavior of nanocrystalline TiO2 is studied using in situ transmission electron microscopy (TEM). These nanoparticles are made using wet chemical techniques that generate the anatase phase of TiO2 with average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate the material undergoes a solid-solid phase transformation to the stable rutile phase between 600° and 900°C. This phase transition is not observed in the TEM samples, which remain anatase up to temperatures as high as 1000°C. Above 1000°C, nanoparticles become mobile on the amorphous carbon grid and by 1300°C, all anatase diffraction is lost and larger (50 nm) single crystals of a new phase are present. This new phase is identified as TiC both from high-resolution electron microscopy after heat treatment and electron diffraction collected during in situ heating experiments. Video images of the particle motion in situ show the nanoparticles diffusing and interacting with the underlying grid material as the reaction from TiO2 to TiC proceeds.