Materials Engineering - Materiálové inžinierstvo (MEMI)
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CORROSION OF COPPER PIPES JOINTS IN SIMULATED OPERATING CONDITIONS
No full textJoining of copper pipes used for liquid media transport are made as demountable and fixation joints. This work deals with corrosion behavior of the joints made by soft soldering, hard soldering and fitting. Corrosion properties of the joints were studied after 11 month exposition in conditions simulated the operating environment. The experiment was made in the 3% NaCl solution, at temperature 20° C for 16 hours and at 80° C for 8 hours per day, the solution was flowing 8 hours by the average rate 0,27 m.s-1. Evaluation of the joints corrosion attacks was made visually, by light and electron microscopy with chemical analyses of corrosion products
INTERNAL FRICTION USE IN MONITORING THE DEGRADATION PROCESSES IN A MATERIAL
No full textDuring the measurement of the fatigue life of material, the specimen undergoes large number of stress cycles. While the observed number of cycles before failure is considered to be the most important result (often the only one), more knowledge can be obtained. Measuring energy consumption of specimen during the cycling, the changes of microstructure of material (especially dislocation structure and crack initialization) can be traced. The evolution of dynamic modulus can be watched on the same equipment. These information becomes very important, especially in the research of gigacycle fatigue strength and fatigue limit below which the continued loading does not lead to structural failure. In this article some remarks on microstructural changes in materials, which can be monitored by nondestructive measurement of internal friction are presented