Role of scanning speed on the microstructure and mechanical properties of additively manufactured Al <sub>2</sub> O <sub>3</sub> ‒ZrO <sub>2</sub>
Zhiwei Xiong, Kai Zhang, Tingting Liu, Zhiguang Zhu, Huiliang Wei, Zhiyong Zou, Wenhe Liao
Abstract
Abstract Melt‐grown Al 2 O 3 –ZrO 2 eutectic (AZ eutectic) ceramics have attracted extensive attention for harsh environment applications. In this work, AZ eutectic ceramic is additively manufactured via one‐step laser powder bed fusion (LPBF). The role of scanning speed on phase formation, crystallographic characteristics, microstructure evolution, and mechanical properties were systematically investigated. The as‐fabricated specimens are mainly composed of α‐Al 2 O 3 and t‐ZrO 2 . Lower scanning speeds induced the formation of cellular structures consisting of randomly oriented ZrO 2 . In contrast, nanometer eutectic lamellar structure with well‐defined multiple crystallographic orientation relationships, for example, {100} Al 2 O 3 || {100} ZrO 2 and {0001} Al 2 O 3 || {001} ZrO 2 , occurred at higher scanning speeds. Both the cell size and lamellar spacing decreased with increasing scanning speed. With the microstructure refinement, the crack propagation mode changes from intergranular to transgranular fracture, leading to progressively enhanced fracture toughness with a maximum value of 7.76 MPa·m 1/2 . The present work could shed light on tailoring the microstructure of LPBF AZ eutectic ceramic via varying processing parameters.