Characterization of Cracking within Thermal Spray Deposits by an Acoustic Emission Method-Extended Abstract

Four-point bend tests with in situ acoustic emission (AE) were used to study the cracking behavior of alumina-3 % titania materials prepared by gas- and water-stabilized plasma technologies (GSP and WSP, respectively). Catastrophic failure was observed for GSP-sprayed samples while WSP-sprayed samples exhibited microcracking before failure. The amplitude and energy distributions were also investigated, and it was determined that the percentage of macrocracks for GSP-sprayed samples is much larger than for WSP-sprayed samples. The processing effects, which induced differences in microstructure, may account for the differences in AE responses.