Investigation on ultrasonic cavitation erosion of TiMo and TiNb alloys in sulfuric acid solution

Surface Alloying and Improved Property of Nb on TC4 Induced by High Current Pulsed Electron Beam

In this paper, an Nb alloying layer on a TC4 alloy was fabricated by using high-current pulsed electron beam (HCPEB) irradiation to improve surface performance. X-ray diffraction (XRD), optical microscopy (OM), laser surface microscope (LSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the phase composition and microstructure of the surface layer. The microhardness, wear tests and corrosion resistance were also examined. The results show that after HCPEB alloying, a Nb-alloyed layer was formed with about 3.6 μm in thickness on the surface of the sample, which was mainly composed of α’-Ti martensite, β-Ti equiaxial crystals, and NbTi₄ particles. After HCPEB irradiation, the surface hardness, wear resistance and corrosion resistance of Nb alloying layer on TC4 alloy were improved compared to the initial samples.

Impact of solid particles on cavitation behaviors and laser-induced degradation in aqueous suspension

A method for degrading organic pollutants in suspension by applying laser-induced cavitation is presented. Cavitation bubbles are produced remotely by laser beams, achieving a purpose of non-contact degradation. In this work, laser-induced bubble dynamics in SiO₂ sand suspension were studied by high-speed imaging. Pulsating characteristics of cavitaiton bubbles in the infinite domain and near a solid boundary were investigated among various laser energies and sand concentrations. Furthermore, the extent of degradation after processing in suspension and the mechanism were analyzed. Results indicate that solid particles in the liquid medium reduce the extent of degradation. However, the extent of degradation may rebound at a proper sand concentration. In addition, compared to several small bubbles in a bubble string (in the infinite domain), a single larger bubble (near a solid boundary) has a much higher degradation ability.

Investigation on Ultrasonic Cavitation Erosion Behaviors of Al and Al-5Ti Alloys in the Distilled Water

Al and Al-5Ti alloys were manufactured by an ultrasonic casting method with a new device, and their ultrasonic cavitation erosion behaviors of Al and Al-5Ti alloys in the distilled water were clarified. The damage mechanism was analyzed by macro photograph, scanning electronic micrograph and three-dimensional morphology, and the results demonstrate that Al-5Ti alloys have better cavitation erosion resistance than Al in terms of the mass loss and the surface damage. The deformation mechanism of Al and Al-5Ti alloys under cavitation erosion is mainly dislocation slip, and the Al3Ti phase enhances the cavitation erosion resistance of Al-5Ti alloys. In addition, the maximum depth of cavitation pits in the Al-5Ti sample is less than that in the Al sample for 31.3%.