Search

The influence of hydrogen on the strength and ductility of 30KhGSA and EI659 steels in quasi-static and shock-loading tests was studied experimentally. The sensitivity of the steels to hydrogenation in air under normal pressure or in hydrogen at a pressure of 25 MPa was determined from the results of tests of as-received and pre-hydrogenated samples at a temperature of 773 K and a hydrogen pressure of 50 MPa for 24 h. It is found that EI659 steel doped with tungsten and vanadium is less sensitive to hydrogenation than 30KhGSA steel doped with manganese and chromium.

The article presents results of comparative tests for the determination of deuterium fluxes permeating through walls of austenitic stainless steel AISI304 (DIN 1.4301) chamber and Al{sub 2}O{sub 3} based ceramic F99.7 chamber. Both chambers represent a piece of φ(ext)=26*φ(int)=22*117 mm{sup 3} tube with spherical bottom ending. It is shown that at 773 K and deuterium pressure of 1200 mbar the permeated deuterium flux through the stainless steel chamber constituted 8*10{sup -5} cm{sup 3}/s, while the flux through ceramic one it did not exceed the sensitivity of the measurement method threshold, namely about 1.5*10{sup -7} cm{sup 3}/s. The ceramic chamber turned out to survive more than 10{sup 3} cycles of heating up to 773 K with no damages. It did not lose its tightness up to 10 bar of internal deuterium pressure. The authors also present test results of a prototype bed for reversible tritium storage. The bed's case was made of alumina based ceramic F99.7, titanium being used as tritide making metal and high frequency induction used for heating the tritide metal. (authors)

A brief review of data for the influence of helium on the hydrogen sorption and mechanical properties of nickel and 12Kh18N10T steel is presented. When in the metallic matrix, helium considerably deteriorates the ductility of these metals. It is shown that 3He present in 12Kh18N10T steel generates high-energy hydrogen traps.

The paper presents research results related to the impact of high-pressure hydrogen (80 MPa) and radiogenic 3He and their synergetic effect on mechanical properties and structure of CrNi40MoCuTiAl alloy within the temperature range from room temperature to 873K.The samples of three different 3He concentrations have been prepared for research: ≈ 30, ≈ 80 and ≈ 190 appm. The buildup of 3He has been fulfilled using «tritium trick» technique.The tests at room temperature have shown the increasing conventional yield strength (σ0.2) and decreasing plasticity characteristics (total elongation Δ5 and reduction of area E) depend on 3He concentration increasing. However at 873 К test temperature the alloy with the maximum 3He (≈ 190 appm) concentration turned out to be more plastic than the alloy with 3He ≈ 30 and 80 appm concentration.

We present some results of studying the influence of high-pressure hydrogen (80 MPa), radiogenic 3He (with concentrations up to 130 appm), and their joint action on the mechanical properties and structure of 12Kh18N10T steel in the temperature range from 293 to 873 K. We describe the procedure of tests of specimens containing 3He. It has been established that the joint action of hydrogen and 3He affects slightly the ultimate strength of the specimens. Saturation of steel with radiogenic 3He by the method of “tritium trick” increases its yield strength. Hardening of the steel caused by helium increases with temperature and 3He concentration and, at 873 K, is accompanied by substantial embrittlement. We also present results of the fractographic analysis of specimens tested under different conditions.

The paper presents results of tritium-structural materials interaction modeling by simultaneous exposure to radiogenic helium-3 and hydrogen (both dissolved and external). This method of synergetic effect of radiogenic helium-3 and hydrogen is a radiation-safe technique to study the tritium impact on mechanical properties of structural materials. Applicability of the method is illustrated by technique and research results on the impact of high-pressure hydrogen (80MPa), helium-3 (concentration ∼140appm) and their synergetic (hydrogen+ 3 He) effecs on mechanical properties of CrNi40MoCuTiAl alloy in temperature range from 20 to 600°C. It has been shown that joint effect of radiogenic helium-3 and hydrogen on mechanical properties of alloy can not be represented as the result of a simple summation of helium and hydrogen embrittlement. Proposed technique of synergetic impact of radiogenic helium-3 and hydrogen allows more correct simulation and investigation in the tritium impact on mechanical properties of materials than individual research in helium or hydrogen embrittlement.

This paper presents research of the hydrogen gas effects on physical and mechanical properties of the precipitation-hardened nickel alloys EP741 and EP99 at pressures up to 65 MPa and temperatures up to 840°C. It has been shown that conventional yield strength, tubular-shaped sample fracture stress and long-term strength are not practically affected by hydrogen. The characteristics of alloy ductility are more susceptible to hydrogen effect. EP741 alloy is especially susceptible to the hydrogen environment effect at temperature of 460°C, and EP99—at temperatures of 20°C and 460°C. Hydrogen permeability relationships for alloys in a wide range of temperature and pressure were obtained.

Displacement of combustion products behind the chemical-reaction front in a condensed system is shown to affect combustion-wave propagation through an inert obstacle. In the experiments, pressed specimens of a Ti+C+20%TiC mixture containing an obstacle in the form of a tantalum band 10 μm to 0.6 mm thick were used. Dependences of the delay of the combustion wave during penetration through the obstacle on the obstacle thickness were obtained for the cases of small (

The possibility of using an axial force probe to detect self-oscillating combustion of samples which yield solid reaction products and some amount of gas is demonstrated. Densified samples of Ti+C+20% TiC containing distilled water in compression pores were used in the experiments. The parameters of the fluctuations in the pressure of the gaseous phase in the reaction front are determined for these samples as they burn in a self-oscillating regime.