Taro Hasegawa

Some Remarks on the Notch Sensitivity in Creep Rupture Properties of Heat-Resisting Alloy A286

Synopsis: The notch sensitivity of creep rupture properties of alloy A286 were reported. The effect of notch forms, heat treatments, melting processes, and the short-time tensile properties on the notch sensitivity were investigated. Changes in hardness, microstructure, and the nucleation and propagation of microcracks at the notch root during creep rupture test were also investigated. Since the plastic flow was constrained under notch condition, the notch sensitivity of this alloy was much affected by microstructure, that is, the resistivity to the nucleation and propagation of microcracks was significant for the notch sensitivity. Reduced resistivity was greatly due to the presence of grain boundary precipitates such as G phase and ri phase, as mentioned in the previous paper (Tetsu-to-Hagane, 46 (1959) 9, p. 1029; zairyo-shiken, 10 ( 1961) 90, p. 70) From the above mentioned point of view, the effects of notch forms, heat treatments, melting processes, and also the short-time properties on the notch sensitivity were discussed according to the experimental results.