Existing oxide dispersion strengthened (ODS) alloys are, besides Ni-based superalloy single crystals, the most creep-resistant materials. The creep resistance of ODS may, moreover, be significantly improved thanks to increasing volume fraction nano oxides by more than one order magnitude so that play a decisive role in strengthening. present experimental study deals with two systems such high-volume oxides, namely, Fe-11Al-1O and Fe-17Cr-7Al-4Y2O3 prepared mechanical alloying hot rolling...

Abstract The paper brings results of high‐cycle fatigue and very‐high‐cycle tests the steel S355 tested during low‐ high‐frequency loading. Two grades structural (S355J0 S355J2) were to gain properties that serve as inputs reliable finite element calculations cyclically loaded structures. Experimental measurements both performed on low‐frequency hydraulic ultrasonic testing systems. Both loading showed higher lifetime for grade S355J2. difference between two studied was more apparent...

Cast polycrystalline superalloys are widely used for critical components in aerospace and automotive industries, such as turbine blades or turbocharges. Therefore, their fatigue endurance belongs to one of the most essential mechanical characteristics. Full-scale testing involves great technical difficulties requires significant experimental effort. The present study evaluates effects microstructural parameters with respect representative a cast blade by separately specimens. For that...

The aim of the paper is to evaluate effect aluminum content on oxidation resistance new-generation oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 are prepared by mechanical alloying. alloys consolidated high temperature rolling followed heat treatment. To study samples isothermally aged in air for 1 h, 4 16 h 64 kinetics, formation mechanism layers analyzed. weight gain steels...

Nickel base superalloys exhibit fatigue fracture behavior with features of brittle-like cleavage cracking under high cycle loading at temperatures up to approximately 800 °C. This specific was already documented in several studies, but a possible mechanism crack propagation this mode has not been made completely clear yet. The aim paper is put more light on the phenomenon by using advanced electron microscopy techniques like back-scattered diffraction (EBSD) and focused ion beam (FIB)...

The study deals with the interaction of creep and high cycle fatigue cast polycrystalline nickel-based superalloy IN 713LC at temperatures. Previous works indicated that lifetime structures was un-affected or even slightly increased in cases superimposed vibrations. reason for this behaviour not well described up to now. Therefore, set tests conducted mean stresses level observe phenomenon. stress kept constant while amplitudes were selected order measure wide range conditions from pure...

Stainless steels, especially AISI 304, are increasingly used civil engineering materials in the last years because they have excellent properties. They for many structures e.g. chemical, energy, bridges etc. The presented study brings results of observation micro-structure and on basic mechanical properties 304 steel. This steel, supplied different profiles by suppliers, can vary considerably, which must be taken into account when designing structures.

Four creep resistant Fe-based oxide dispersion strengthened (ODS) alloys with a significantly high amount of dispersed nanoprecipitates have been investigated. One Fe-Al-O and three Fe-Al-Cr-Mo-Y2O3 systems different chemical composition by yttrium nano-oxides prepared mechanical alloying powders consolidation hot rolling leading to ultrafine grained microstructure due dynamic recrystallization. The thermal stability the precipitates, effects processing on (grain precipitate size) properties...

Lifetime of MAR-M 247 Ni-based superalloy was experimentally studied under high-frequency cyclic loading (120 Hz) with constant tensile mean stress σm = 300 MPa at temperature 900 °C in air. The amplitude σa changed order to investigate the lifetime a wide range conditions, from pure creep fatigue. superposition on does not influence specimen until threshold value is reached. Scanning electron microscopy utilized for fracture surface observation aim identify governing damage mechanisms...

The effect of high-frequency cycling (120 Hz) superimposed on high tensile mean stress a lifetime cast Ni-base superalloys IN 713LC at 800 °C and MAR-M 247 900 was investigated. It has been found that both the alloys exhibit qualitatively similar behavior in creep/fatigue loading conditions. Superposition small amplitudes does not influence time to fracture until amplitude reaches threshold value, which is dependent stress. higher value. observed governed by two mechanisms: (a) formation...

B1914 is a nickel-based superalloy with an increased amount of B (boron) and C (carbon) to reach adequate borides carbides in the cast structure ensuring improved creep properties. However, influence on material high-cycle fatigue properties not sufficiently described. The present study brings experimental results polycrystalline boron-rich superalloy, obtained at temperatures 800, 900 950 °C. was processed by hot isostatic pressing (HIP) diminish casting defects. tests were performed...

The presented study is focused on experimental results of high-cycle fatigue life a cast polycrystalline nickel-based superalloy IN 738LC at temperatures 800, 900, and 950°C. absence hot isostatic pressing (HIP) led to the occurrence casting defects in microstructure. tests were performed symmetrical loading laboratory air. fracture surfaces specimens studied by scanning electron microscopy describe influence temperature damage mechanism crack initiation. Change primary propagation from...

Excellent creep strength of the ODS steels is associated with an attractive interaction between dislocations and oxides. The aim this study to explore Fe-Al-O Fe-Al-Cr-Y-O systems high oxygen content (up 1.5 wt %) represented by alumina or yttria oxides 5 vol. identify potentials new generation alloys. basic material prepared from Fe 10 11 wt. % Al. Theoretical models showed stability Al even above 1000°C, while practical results show coarsening time at these temperatures. Stability Y about...

Design of materials for severe high temperature mechanical exposures can be assisted by a newly developed 3D discrete dislocation dynamics model which tailored numerical simulation hot tensile tests.The is based upon the linear theory elasticity.The structure represented short straight segments.This allows straightforward calculation stress fields and, subsequently, driving forces at any point in cell as sum contributions individual segments, osmotic forces, externally applied stress, misfit...