数値解析による一方向凝固NI基超合金のき裂成長挙動におよぼす予損傷の効果

抄録

Directionally solidified Ni-base superalloy is used for gas turbine blades for high efficiency thermal power plant. There are many studies using a smooth specimens for directionally solidified Ni-base superalloy. However, these are not so many researches which concern the mechanical behavior of a notched specimen. From the view point of application to actual components, it is important to conduct the research for a notched specimen. And, directionally solidified Ni-base superalloy has large crystal grain. Therefore, crack growth behavior and crack growth life are considered to be affected by crystal orientation around the crack. However, effect of crystal orientation on crack growth life caused by inhomogeneous of grain distribution has not been clarified. In this study, by conducting mechanical analysis using the designed 2-dimensional elastic-plastic creep finite element analysis, scattering behavior of creep crack growth life and effect of pre-damage on creep crack growth behavior for directionally solidified Ni-base superalloy was analyzed.