Ultrasonic Characterization of Consolidated Rapidly Solidified Powders: Application to Type 304 Stainless Steel

摘要

These results have shown that distinct microstructural features in the consolidated forms of these rapidly solidified powders can be observed through ultrasonic measurements. In general,, the presence or absence of remnant particle boundaries could be observed with results depending on the original particle size, particle extrusion occurring during the consolidation process, and the type of consolidation process used. Annealing tests dramatically demonstrated microstructural evolution in these materials, including the onset of recrystallization zones, grain growth, helium gas condensation into bubbles, and the effects of porosity. All of these features were observable with the ultrasonic measurements in a nondestructive way. Generally, both backscatter energy and attenuation results yielded similar information, with the backscatter technique being significantly simpler to implement and particularly useful for comparative measurements where adequate normalization can be maintained. (ERA citation 11:051215)