Electric Surface Effects in Solid Plasticity and Strength

Surface Modification and Contact Interaction of Particles

“…[54,70,71] Catalysis assisted rupture of surface bonds may result also in creating new adatoms and, correspondingly, in accelerating the adatoms diffusion and particle sintering, [72] i.e., in increasing the strength, or achieving the same interparticle contacts and strength at lower sintering temperatures (catalysis enhanced sintering-CES). [75,76] To complete this consideration of the influence of adsorption modification of the surface on mechanical behavior, we include here also some data on the manifestation of such influences in compact solids. [73,74] Surface modification effects can be determined by the influence of medium and adsorption on the damageability of a solid surface, particularly, on the deformation and fracture processes in the thinnest subsurface layers.…”

“…15 and 16. [75,76] (4). This phenomenon, the adsorption caused decrease in strength (ADS), or the Rehbinder effect was discovered by Rehbinder in 1928: he observed facilitation of some crystal (quartz, fluorite) cleavage in surfactant solutions, and explained the nature of this effect as a result of a decrease in the surface energy of solid phase, i.e., in the work of new surfaces formation during fracture.…”

Microscratching in an electrochemical cell. Effect of gallium on the surface deformation in aluminum

“…According to the described method, the microscratching of aluminum (99.999%) was carried out in a 10 wt.% aqueous solution of gallium sulfate under a load of 10 g applied to the indenter (diamond pyramid) moving along the surface with a velocity of 10mm/min. This result may be considered as an essential predominance of the plasticizing effect over the embrittling one due to specific conditions of a relatively mild loading mode and extremely high initial plasticity of the very pure metal [9,18]. 1, we present the SEM-images (• 1000) of two grooves made in the same specimen in the absence of electric current (a) and in the presence of a current through the specimen surface with a density of 6.8 mA/cm 2 (b).…”

“…The tests become particularly informative for small loads on the indenter, as in micro-and ultramicrosclerometry developed by the authors in [13][14][15][16][17][18]: these methods allow one to observe the appearance of the very first dislocations along the path of the indenter, i.e., elementary events of damage, and the transition from the elastic behavior of the material to its plastic behavior in the contact zone and to the brittle response of the material depending on the pH value, admixtures of surfactants in aqueous solutions, and other characteristics of the medium. The tests become particularly informative for small loads on the indenter, as in micro-and ultramicrosclerometry developed by the authors in [13][14][15][16][17][18]: these methods allow one to observe the appearance of the very first dislocations along the path of the indenter, i.e., elementary events of damage, and the transition from the elastic behavior of the material to its plastic behavior in the contact zone and to the brittle response of the material depending on the pH value, admixtures of surfactants in aqueous solutions, and other characteristics of the medium.…”

“…The dislocation model of the plasticizing effect caused by surface-active media was considered in [9,18,[26][27][28][29]. It was shown that the mobility of subsurface dislocation segments is opposed by a force required for the crea- For the evaluation of the depth of this influence, we can use some results of our calculations of the parameters of rolling of a thin strip (foil) carried out by the method of finite elements both for plasticized and hardened surface layers [30,31 ].…”