The dynamics of transient plasmas generated by high-fluence nanosecond laser ablation has been investigated by recording the ionic current with a Langmuir probe. Systematic measurements have been carried out on a plasma produced in vacuum by Nd:YAG laser irradiation of a copper target. The temporal evolution of the ionic current for different fluences was investigated, revealing the presence of some periodic oscillations. A theoretical model is proposed in order to describe the nonlinear behavior of the expanding plasma by assuming that the motion curves of the ablated particles are fractals. The behaviors predicted by the proposed theoretical model are in good agreement with the experimental findings.

This Paper Aims to Determine by Experiment Total Force and Stress of Deformation Depending on Punch Stroke and the Level of Deformation on Severe Plastic Deformation of Aluminum by Multiaxial Cold Forging. the Deformation Force in Multiaxial Forging Depends on a Number of Parameters of whom the most Important are: Strain, the Flow Force of Aluminum, Deformation Speed, the Friction between the Material and the Die, Shape and Size of Die, the Dimensions of Deform Profile, Shape and Dimensions of Workpiece, Temperature Variation during the Process, Physical and Mechanical Properties of the Workpiece Material, the Structural Inhomogeneity of Workpiece Material. the Deformation Process is Discontinuous and Includes Deformation Processes that Define a Cycle of Severe Plastic Deformation. this Paper Aims to Determine the Force and Stress Corresponding to the First 12 Cycles of Severe Plastic Deformation.

The carabiners are metallic links used to quickly connect the components of personal fall arrest equipment. Because these systems are used in corrosive environments, the carabiners must possess good corrosion resistance properties. In order to improve these properties, a phosphate layer was chemically deposited by converting on the carabiner material surface. This paper presents the microscopic analysis of the phosphated layer and the galvanic corrosion behavior of phosphated carbon steel, coupled to duralumin and initial carbon steel. Corrosion resistance has been studied for Black Sea water and fire extinguishing solution.