[en] The possibility is shown for application of the kinetic equation of creep, suggested lately for structurally stable steels, to high-nickel ageing alloys. The equation describes strains in high-temperature ageing 03Kh20N45M4BCh and 03Kh20N45MBRTs alloys at 823-1023 K temperatures. The temperature dependences for the coefficients in thquations considered are determined

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[en] The precipitation hardened Inconel X-750 is extensively used in both PWR and BWR as bolts, pins, spring components, etc., mainly because of this alloy's excellent high temperature strength and good oxidation and corrosion resistance. However, this alloy has experienced some intergranular stress corrosion cracking. It has been reported that the SCC resistance of Inconel X-750 can be improved by direct aging in the precipitation regime of 704 to 871⁰C. Therefore, the microstructural changes that occur when Inconel X-750 is thermally treated between 704⁰C and 871⁰C for up to 200 hours following a 2-hour solution anneal at 1075⁰C, or 1149⁰C, or 1204⁰C has been studied. Optical, transmission electron, and scanning and Auger electron microscopy were used in order to establish the most appropriate aging sequence for this alloy which will produce a suitable precipitation morphology and distribution of secondary carbides and intermetallics. The precipitation morphology and analysis of γ' (L1₂), secondary M₂₃C₆ and primary MC carbide phases for each heat treatment cycle were studied using TEM techniques. The coarsening kinetics of the γ' particle growth obeyed the time-law prediction of Lipshitz-Slazor-Wagner theory of diffusion controlled growth at all aging temperatures. The γ' precipitate lost coherency by the nucleation of dislocation loops within the precipitate, the interaction of dislocation at the interface and attraction of matrix dislocations to the particle/matrix interface

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[en] An upgrade of the vessel protection system for DIII-D is in progress. The ceiling, floor, and inner wall are being armored to enable operation of double null diverted plasmas and to enable the use of the inner wall as a limiting surface. The present armor configuration is the subject of this paper. It involves partial coverage of the vessel wall with a combination of Inconel X-750 tiles and Inconel tiles with 1 cm graphite caps brazed to the plasma facing surface. The graphite is located only in the areas of neutral beam shinethrough and divertor targets on the floor. The existing brazed design has had limited success at the present operational energy levels which are below the capability of the machine. The new armor tile design utilizes the existing mounting studs and stud pattern in the vessel and is compatible with existing and planned diagnostics

[en] Fatigue crack growth rates, measured in INCONEL X-750 at 650⁰C and at 10, 1, 0.1, 0.01 Hz, were correlated to the cyclic properties, yield strengths and fatigue lives. Experimental data show that, at frequencies >0.1 Hz, fatigue crack growth processes are mainly cycle dependent and are essentially due to the dependence of cyclic yield strength on strain rate. At lower frequencies fatigue crack growth rates increase dramatically and experimental results are much higher than theoretical values calculated on the base of present CTOD models. This confirms the presence of time-dependent processes which were also confirmed by fractographic studies. (orig.)

[en] Aging of the 03Kh20N45M4BCh alloy in the 500-750 deg C temperature range is investigated, vacancy swelling of the alloy is observed here. Phases precipitating in the material are shown to result in appearance of elastic distortions in the lattice and effective breaking of dislocations. The mentioned factors in combination with the experimentally observed metastability of the 03Kh20N45M4BCh alloy are responsible for its high resistance to vacancy swelling