抄録
A fractographic study has been made on the fatigue fracture behaviour of sintered titanium compact compared with the case of wrought titanium specimen.
The fractograph of wrought titanium specimen showed the typical fatigue crack propagation mode, namely, a crack nucleation along the active slip plane oriented at 45°to the applied stress axis (stage I), a crack propagation normal to the stress axis accompanied with striations and tire-tracks (stage II), and the dimple pattern owing to the final fracture (stage III). The similar fatigue crack propagation mode composed of the above mentioned three stages was also recognized in a sintered titanium specimen, however, in this case, the river pattern was noticed in any three crack propagation stages.
Owing to the much more brittleness than expected from the oxygen content in P/M specimen, the fatigue ratio of 0.26 for the P/M Ti specimen is confirmed to be extremely low, compared with the value of 0.48 for I/M Ti specimen.
