文摘
A knee point appears in the fatigue crack growth rate curve of the small fatigue crack in Ti-6.5Al-2Zr-1Mo-1V alloy. At the knee point, the crack fracture mode transitions from a crystallographic faceted fracture to a striation type. Before the knee point, the crack growth mode change causes a zigzag crack growth path. After the knee point, the crack growth path transitions from zigzag to linear.