スモールパンチ試験法によるTi-43Al-5V-4Nb合金のクリープ特性評価

抄録

It is required to evaluate the high-temperature strength of turbine blade for a jet engine with a miniaturized specimen, because it is too small to investigate the strength distribution with a standard specimen. In this study, the small punch (SP) testing technique was applied to the wrought TiAl alloy (Ti-43Al-5V-4Nb) for the creep property assessment. The SP creep tests were carried out at the temperatures of 760 and 800°C and under the load range from 300 to 600 N using a small disk-type specimen (8 mm in diameter, 0.5 mm in thickness). In order to compare the results obtained from the SP creep test with those from the uniaxial creep test, the SP load (F) was converted to the stress (σ) with the load/stress conversion coefficient (F/σ), which was determined based on the high-temperature SP test results. The experimental results revealed the SP fracture characteristic was significantly different depending on the testing temperature, that is, between 760℃ and 800°C. It was also found that the SP creep rapture data were well correlated with the uniaxial ones using the obtained F/σ.