拉伸速率对FGH95缺口小试样断裂性能的影响

Study on the Influence of Loading Rate on Fracture Characteristic of FGH95 Notched Specimen

研究了不同加载速率和不同的缺口形状对粉末冶金FGH95缺口小试样拉伸断裂性能的影响.结果表明:名义断裂应力σnom随着加载速率的增大而减小;仅对具有相同缺口深度的缺口试样,σnom随着名义应力集中因子Kt的增大而减小,缺口深度对断裂应力的影响远大于缺口形状,当缺口深度达到某一数值,将产生缺口强化现象.随着加载速率的增大,缺口敏感系数Cm呈下降趋势,应力集中因子越大的试样,缺口敏感性越强.γ′沉淀粒子的强化作用和高温动态回复对FGH95高温变形起主要作用.

Experiment was performed to investigate the influence of loading rate and notch effect on FGH95 notched small specimen.The results show that nominal fracture stress σnom decreases with the increase of the loading rate,and decreases with the increase of nominal stress concentrate factor Kt increase for the notched specimen with same notch depth.The notch depth plays a more significant role for the nominal fracture stress than notch shape.And the notch would cause notch strengthen if notch depth is up to a certain value.With the loading rate increasing,the coefficient of notch sensitivity Cm decreases,and notch sensitivity increases with Kt increase for notch softening specimen.Strengthen of γ′ precipitation particle and high-temperature dynamic recovery play a major role in the high temperature deformation process of FGH95.