DEVELOPMENT OF A MODIFIED A286 ALLOY WITH IMPROVED STRENGTH AT ELEVATED TEMPERATURE AND AN EVALUATION OF ITS HYDROGEN EMBRITTLEMENT SUSCEPTIBILITY

摘要

A modified A286 alloy was developed with the aim of improving elevated temperature strength. The alloy was evaluated using a tensile test and a creep rupture test. Microstructure observations of the modified A286 alloy revealed that W and Ti carbides were precipitated at the grain boundaries and that no η phases were observed. The modified alloy showed higher tensile strength in a test at 625°C and a longer rupture time in a creep rupture test at 650°C relative to the conventional A286 alloy. Hydrogen embrittlement susceptibility was evaluated using a low-strain-rate tensile test with hydrogen-charged specimens. From a comparison of the reduction of area, it was determined that the hydrogen embrittlement resistance of the modified A286 was equal to or greater than that of conventional A286.