Vliv vodíku na fyzikálně-mechanické charakteristiky superslitiny IN738LC

Abstract

Study of hydrogen effect on mechanical properties was carried out on samples of IN-738LC superalloy. Two sets for tensile tests were prepared: hydrogen-charged and hydrogen-free. Heat treatment in flow of hydrogen was performed at 800 °C for 4 hours. Specimens were tensile tested at a strain rate 5.8x10-5.s-1. Hydrogen presence in microstructure led to an increase in both mean yield strength and ultimate stress. Hydrogen content in two samples hydrogen-charged was determined using LECO RH600 analyzer. Metallographic, fractographic study and microanalysis of samples after tensile test were carried out. Casting defects in the microstructures were observed using optical microscopy. Structural phase analysis of phases was performed using EDX microprobe. The character of fracture surfaces was observed on the hydrogenated and hydrogen-free tensile samples by means of SEM JEOL JSM-6490LV. Hydrogen affected a change of fracture feature of superalloy samples.