Direct Observations of Changes in Ferroelectric Domain Configurations Around the Indentation and Ahead of the Crack Front

The indentation response of polycrystalline lead zirconate titanate (PZT) with varying ferroelastic domain configurations is investigated using nano and micro indentation. In the fully depoled state (with completely random domain configurations), PZT exhibit higher hardness, H as compared to poled PZT. Severe cracking is observed at the imprint corners at high indentation loads and the ferro-elastic domain configurations are visualized in the vicinity and ahead of the crack using piezoresponse force microscopy. The domains remain fully plastic in the regions from where the crack has propagated and just ahead of the crack while farther from the crack their remain elastic. The results are rationalized using remanent strain, ε ^r results highlight the toughening mechanisms in the as poled PZTs. and converse piezocharge coefficient, d ^*33 measured around microcrack. The results highlight the toughening mechanisms in the as poled PZTs.