円柱圧子押込み試験によるクリープ構成式推定手法の効率化に関する研究

抄録

Identification of creep exponent n and creep coefficient k in Norton’s law is very important to characterize creep deformation of a high-temperature material. We have previously proposed the high-temperature indentation creep test with a spherical ball for the estimation of the n and k as an alternative method to the uniaxial creep test. However, this creep test is needed to be interrupted every 100 h to measure impression radius. To prevent this problem, more practical estimation method based on the high-temperature indentation creep test with a cylindrical indenter was developed. This method allows us to estimate the n and k from the relationship between impression stress and indentation rate continuously measured during testing. So far, it is confirmed that n and k are properly estimated by results of cylinder indentation test which is conducted for each loading condition. In this study, continuous test was conducted, which can obtain all data needed for estimation of n and k at once. In order to validate this method, the high temperature indentation test was conducted with a cylindrical alumina indenter to estimate the n and k of pure aluminum A1050 plates. As a result, it was demonstrated that the n and k estimated from the developed method coincide with those estimated from the conventional methods. Furthermore, it was found that the developed method needs shorter time for the estimation as compared with the conventional methods.