Linking flexural strength and strength‐limiting flaws in additively manufactured alumina with print parameter variations

Abstract

AbstractAdvancing the adoption of lithography‐based ceramic manufacturing (LCM) for structural applications requires understanding how processing parameters impact the printed material's flaw population and failure behavior. Exploratory studies on LCM alumina have mixed results regarding print parameter influence on strength and past fractography is insufficiently complete to guide process engineering for better performance. We perform four‐point flexural strength characterization and comprehensive fractography of LCM alumina to evaluate the impact of processing parameters including orientation, layer height, and curing energy on strength‐limiting defects. Characteristic strengths for fully dense, high‐purity LCM alumina are near or above conventionally processed alumina within the manufacturable range of print parameters studied in this work. Conversely, the Weibull modulus varies greatly (m = 3.8–19.5) depending on print parameters. The dominant strength‐controlling defects all have a printing‐based origin, but vary between delamination, surface texture, and bubbles depending on print orientation. Lowest performance results from alignment of the print axis along the bar length, yielding a low Weibull modulus associated with weak delamination flaws that are not appreciably improved by varying print layer height or curing energy.