Paper presents the results of evaluation of heat resistance and specific heat capacity of MAR-M-200, MAR-M-247 and Rene 80 nickel
superalloys. Heat resistance was evaluated using cyclic method. Every cycle included heating in 1100°C for 23 hours and cooling for 1
hour in air. Microstructure of the scale was observed using electron microscope. Specific heat capacity was measured using DSC
calorimeter. It was found that under conditions of cyclically changing temperature alloy MAR-M-247 exhibits highest heat resistance.
Formed oxide scale is heterophasic mixture of alloying elements, under which an internal oxidation zone was present. MAR-M-200 alloy
has higher specific heat capacity compared to MAR-M-247. For tested alloys in the temperature range from 550°C to 800°C precipitation
processes (γ′, γ′′) are probably occurring, resulting in a sudden increase in the observed heat capacity.
Operating conditions turbocharger (high temperature and corrosive environment) mean that the device is classified into one of the most elements of the emergency drive unit of the car. The failure rate can be reduced through the use of modern heat-resistant materials, which include based alloys FeAl intermetallic phase. Intermetallic alloys belong to the group of materials known as prospective due to their advantageous properties, in particular their high specific strength, high melting point and good resistance to corrosion and oxidation at high temperatures. In the article presented results of the research axis roll control system variable geometry blades made of intermetallic alloy Fe40Al5Cr0,2TiB as a substitute so far made of austenitic steel. A verification service conditions, comparing the degradation of the material previously used by manufacturers of turbochargers for elements of the control system degradation axes made of intermetallic alloy Fe40Al5Cr0,2TiB. The study consisted of determining microstructure and corrosion products after use. Observations of the structure and the surface of the corrosion tests were performed using light microscopy, scanning electron microscopy and X-ray microanalysis EDS chemical composition.
High-temperature plastic properties of heat-resistant stainless steel X15CrNiSi 20-12 were assessed on the basis of hot tensile tests and nil strength tests. The results were supported by metallographic analyses using SEM and EDX analysis. The formability of the investigated steel can be divided into roughly three temperature areas. In the temperature range of 900°C to about 1050°C, formability was negatively affected by precipitation of carbide particles at grain boundaries. As the temperature rose to 1200°C, these particles dissolved, resulting in an increase in formability. Further temperature increases resulted in a relatively steep drop in formability caused by overheating of the material. The nil ductility temperature of 1280°C and the nil-strength temperature of 1362°C were determined. The Plastic and strength properties of the investigated material were compared with the deformation behavior of the reference steel X5CrNi 18-10, which shows a significantly wider range of suitable forming temperatures.
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