In situ observations of cracking in constrained sintering

Abstract

In this paper, we examine the long‐standing problem of cracking during constrained sintering of a powder aggregate. Using binder jet 3D printing, we prepare ceramic green bodies in the form of center‐notched panels, then use in situ imaging to observe how cracks nucleate and grow from the notch as the material sinters under restraint. Quantitative image analysis allows us to identify important characteristics of the sinter‐cracking process, indicating a framework for analyzing the problem and developing methods for avoiding it, including representation of sinter‐cracking as a creep crack growth process, use of fracture mechanics parameters to design specimen geometries that do not exceed critical stress intensities, and the possibility of exploiting the inherently ductile nature of sinter‐cracking to mitigate damage.