Effect of the intermediate action of hydrostatic pressure on the high-temperature creep and durability of copper

The intermediate action of hydrostatic pressure on the high-temperature creep of copper is studied at various creep stages. Tests performed at a constant tensile stress of 12.5 MPa at 773 K show that the application of a pressure at the creep third stage decreases the steady-state creep rate and extends the time to failure. At the steady-state stage of creep, the effect of the pressure may be ignored. At pressures of up to 1 GPa, this effect is found to be only related to healing of grain-boundary porosity. At higher pressures, the steady-state creep rate is governed by porosity healing and structural changes.     

Initial stage of void and crack healing in polycrystalline metals under uniform compression

The effect of uniform pressure and temperature on voids and cracks located at grain boundaries in polycrystalline metals is studied. A high-sensitivity method for measuring density, scanning electron microscopy, and optical microscopy were used to analyze the healing of cavities. The results obtained are discussed on the basis of the existing notion of the kinetics of healing under pressure at various temperatures.     

Kinetics of pore healing and copper hardening upon uniform compression

X-ray diffraction is employed to determine the dependence of the mobile dislocation density on the strain arising upon healing porous copper subjected to a hydrostatic pressure of up to 1500 MPa. The mean free path of dislocations is estimated as a function of the compression strain, strain rate under pressure, rate of dislocation generation, and mean velocity of their motion.     

Stress Corrosion Cracking of Metals and Alloys in Aggressive H2S–CO2–Cl– Environments

Technical Physics - We have analyzed the data on stress corrosion cracking of steels of various grades in acidic H2S–CO2–Cl– solutions. For the active region of corrosion, we have...     

The Formation of Single-Photon IR Wave Packets with an Orbital Angular Momentum Using Vortex Phase Plates

Optics and Spectroscopy - Specific features of the construction and recording of axially symmetric vortex fields using diffraction optical elements, which can be used for generating single-photon...     

Activity of mono-and disubstituted derivatives of 1,4-benzoquinone and allylamine in cationic polymerization

Cationic polymerization of mono- and disubstituted derivatives of 1,4-benzoquinine and allylamine in the presence of hydrochloric acid was studied. The optimal conditions were found and the kinetic parameters of the process were evaluated.     

Cationic polymerization of a derivative of allylamine and 1,2-naphthoquinone

Cationic polymerization of a monomer derived from allylamine and 1,2-naphthoquinone was studied by polarography. The optimum conditions and kinetic characteristics of the process were found.     

Effect of the microstructural porosity parameters on the fracture and deformation of copper during creep at 773 K

The parameters of intergranular fracture of copper during creep under tension at T = 773 K and σ = 12.5 MPa are determined, and the contribution of grain-boundary porosity to the increase in the creep rate at stage III is estimated. The increase in the creep rate is shown to occur due to the pore-induced decrease in the grain boundary area, an increase in the mobile-dislocation density, and the deformation of the material because of the formation of pores and cracks.